{"id": "boshkayev2023quasiperiodic", "title": "Quasi-periodic oscillations in rotating and deformed spacetimes", "abstract": "Quasi-periodic oscillation (QPOs) analysis is important for understanding the dynamical behavior of many astrophysical objects during transient events such as gamma-ray bursts, solar flares, magnetar flares, and fast radio bursts. In this paper, we analyze QPO data in low-mass X-ray binary (LMXB) systems, using the Lense-Thirring, Kerr, and approximate Zipoy-Voorhees metrics. We demonstrate that the inclusion of spin and quadrupole parameters modifies the well-established results for the fundamental frequencies in the Schwarzschild spacetime. We interpret the QPO data within the framework of the standard relativistic precession model, allowing us to infer the values of the mass, spin, and quadrupole parameters of neutron stars in LMXBs. We explore recent QPO data sets from eight distinct LMXBs, assess their optimal parameters, and compare our findings with results in the existing literature. Finally, we discuss the astrophysical implications of our findings.", "keyphrases": ["neutron stars", "fundamental frequencies", "quasi-periodic oscillations"]}
{"id": "fangyi2023optical", "title": "Optical Appearance of Eccentric Tidal Disruption Events", "abstract": "Stars approaching supermassive black holes can be tidally disrupted. Despite being expected to emit X-rays, TDEs have been largely observed in optical bands, which is poorly understood. In this Letter, we simulate the tidal disruption of a 1 M\u2299 main sequence star on an eccentric (e=0.95) orbit with a periapsis distance one or five times smaller than the tidal radius (\u03b2=1 or 5) using general relativistic smoothed particle hydrodynamics. We follow the simulation for up to a year post-disruption. We show that accretion disks in eccentric TDEs are masked by unbound material outflowing at \u223c10,000 km/s. Assuming electron scattering opacity, this material would be visible as a \u223c100 au photosphere at \u223c104 K, in line with observations of candidate TDEs.", "keyphrases": ["tidal disruption events", "supermassive black holes", "optical transients", "hydrodynamical simulations"]}
{"id": "lai2023improving", "title": "Improving Constraint on \u03a9_m from SDSS Using Marked Correlation Functions", "abstract": "Large-scale structure (LSS) surveys will increasingly provide stringent constraints on our cosmological models. Recently, the density-marked correlation function (MCF) has been introduced, offering an easily computable density-correlation statistic. Simulations have demonstrated that MCFs offer additional, independent constraints on cosmological models beyond the standard two-point correlation (2PCF). In this study, we apply MCFs for the first time to SDSS CMASS data, aiming to investigate the statistical information regarding clustering and anisotropy properties in the Universe and assess the performance of various weighting schemes in MCFs. Upon analyzing the CMASS data, we observe that, by combining different weights (\u03b1=[\u22120.2,0,0.2,0.6]), the MCFs provide a tight and independent constraint on the cosmological parameter \u03a9m, yielding \u03a9m=0.293\u00b10.006 at the 1\u03c3 level, which represents a significant reduction in the statistical error by a factor of 3.4 compared to that from 2PCF. Our constraint is consistent with recent findings from the small-scale clustering of BOSS galaxies <cit.> within the 1\u03c3 level. However, we also find that our estimate is lower than the Planck measurements by about 2.6\u03c3, indicating the potential presence of new physics beyond the standard cosmological model if all the systematics are fully corrected. The method outlined in this study can be extended to other surveys and datasets, allowing for the constraint of other cosmological parameters. Additionally, it serves as a valuable tool for forthcoming emulator analysis on the Chinese Space Station Telescope (CSST).", "keyphrases": ["large scale structure of universe", "dark energy", "cosmological parameters", "marked weighted correlation function"]}
{"id": "mcgaugh2023early", "title": "Early Galaxy Formation and the Hubble Tension", "abstract": "A tension between the expansion rate of the universe obtained from direct measurements and that inferred from fits to the acoustic power spectrum of the Cosmic Microwave Background (CMB) radiation has emerged as higher multipoles have been incorporated into CMB fits. This temporal evolution is suggestive of a systematic effect at fine angular scales, and may be related to the observation of unexpectedly massive galaxies at high redshift. Such objects could cause anomalous gravitational lensing of the surface of last scattering, which in turn may affect the best-fit value of H0. If so, the Hubble tension may be the result of a systematic effect in the fitting of CMB data rather than a systematic error in local measurements.", "keyphrases": ["early universe", "galaxy formation", "large-scale structure of the universe"]}
{"id": "broughton2023mitigation", "title": "Mitigation of the Brighter-Fatter Effect in the LSST Camera", "abstract": "Thick, fully depleted charge-coupled devices (CCDs) are known to exhibit non-linear behavior at high signal levels due to the dynamic behavior of charges collecting in the potential wells of pixels, called the brighter-fatter effect (BFE). This particularly impacts bright calibration stars, which appear larger than their intrinsic shape, creating a flux-dependent point-spread function (PSF) that if left unmitigated, could make up a large fraction of the error budget in Stage IV weak-lensing (WL) surveys such as the Legacy Survey of Space and Time (LSST). In this paper, we analyze image measurements of flat fields and artificial stars taken at different illumination levels with the LSST Camera (LSSTCam) at SLAC National Accelerator Laboratory in order to quantify this effect in the LSST Camera before and after a previously introduced correction technique. We observe that the BFE evolves anisotropically as a function of flux due to higher-order BFEs, which violates the fundamental assumption of this correction method. We then introduce a new sampling method based on a physically motivated model to account these higher-order terms in the correction, and then we test the modified correction on both datasets. We find that the new method corrects the effect in flat fields better than it corrects the effect in artificial stars which we conclude is the result of a unmodeled curl component of the deflection field by the correction. We use these results to define a new metric for the full-well capacity of our sensors and advise image processing strategies to further limit the impact of the effect on LSST WL science pathways.", "keyphrases": ["ccds", "lsst", "brighter-fatter effect", "flat field statistics", "pixel size variation", "point-spread function", "instrument signature removal", "weak lensing"]}
{"id": "young2023insights", "title": "Insights into the first and second hydrostatic core stages from numerical simulations", "abstract": "The theory of how low mass stars form from the collapse of a dense molecular cloud core has been well-established for decades. Thanks to significant progress in computing and numerical modelling, more physical models have been developed and a wider parameter space explored to understand the early stages of star formation more fully. In this review, I describe the expected physical properties of the first and second core stages and how the inclusion of different physics affects those predicted characteristics. I provide an overview of chemical models and synthetic observations, looking towards the positive identification of the first core in nature, which remains elusive. However, there are a few likely candidate first cores, which are listed, and I briefly discuss the recent progress in characterising the youngest protostellar sources. Chemistry will be instrumental in the firm identification of the first core so we require robust theoretical predictions of the chemical evolution of protostellar cores, especially of the first and second core outflows. Looking ahead, simulations can shed light on how the protostellar collapse phase shapes the evolution of the protostellar disc. Simulations of dust evolution during protostellar core collapse show there is significant enhancement in grain size and abundance towards the centre of the core. Chemical models show that the warm, dense conditions of the first core drive chemical evolution. There is a wide scope for further study of the role that the first and second core stages play in determining the structure and composition of the protostellar disc and envelope and, of course, the eventual influence on the formation of planets.", "keyphrases": ["star formation", "hydrodynamics", "radiative transfer", "magnetohydrodynamics"]}
{"id": "sethi2023variable", "title": "Variable Chaplygin Gas: Contraining parameters using FRBs", "abstract": "We investigate the cosmological constraints on the Variable Chaplygin gas model with the latest observational data from the Fast Radio Bursts and SNeIa (Pantheon+SHOES). The Variable Chaplygin gas model is shown to be compatible with Type Ia Supernovae and Fast Radio Burts. We have obtained tighter constraints on cosmological parameters Bs and n, using the the FRB data set. By using the Markov chain Monte Carlo (MCMC) method on the SNeIa data set, we obtain Bs=0.1956 +- 0.1047 , n= 1.3581 +- 1.1678 and H0= 70.3902 +- 0.6381 and we obtain Bs= 0.1780 +-0.1069 , n= 1.2633+- 1.2433 and H0=70.397 +- 0.6597 from the FRB data set. We are able to get a good agreement between the H0 values from the two data sets.", "keyphrases": ["variable chaplygin gas", "fast radio bursts", "sne ia", "cosmology"]}
{"id": "taaki2023robust", "title": "Robust Detrending of Spatially Correlated Systematics in Kepler Light Curves Using Low-Rank Methods", "abstract": "Light curves produced by wide-field exoplanet transit surveys such as CoRoT, Kepler, and TESS are affected by sensor-wide systematic noise which is correlated both spatiotemporally and with other instrumental parameters such as photometric magnitude. Robust and effective systematics mitigation is necessary to achieve the level of photometric accuracy required to detect exoplanet transits and to faithfully recover other forms of intrinsic astrophysical variability. We demonstrate the feasibility of a new exploratory algorithm to remove spatially-correlated systematic noise and detrend light curves obtained from wide-field transit surveys. This spatial systematics algorithm is data-driven and fits a low-rank linear model for the systematics conditioned on a total-variation spatial constraint. The total-variation constraint models spatial systematic structure across the sensor on a foundational level. The fit is performed using gradient descent applied to, a variable reduced least-squares penalty and a modified form of total-variation prior; both the systematics basis vectors and their weighting coefficients are iteratively varied. The algorithm was numerically evaluated against a reference principal component analysis, using both signal injection on a selected Kepler dataset, as well as full simulations within the same Kepler coordinate framework. We find our algorithm to reduce overfitting of astrophysical variability over longer signal timescales (days) while performing comparably relative to the reference method for exoplanet transit timescales. The algorithm performance and application is assessed and future development outlined.", "keyphrases": ["exoplanet detection methods", "astronomy data analysis", "wide-field telescopes", "surveys"]}
{"id": "milli2023insight", "title": "Insight from laboratory measurements on dust in debris discs", "abstract": "Extreme adaptive optics instruments have revealed exquisite details on debris discs, allowing to extract the optical properties of the dust particles such as the phase function, the degree of polarisation and the spectral reflectance. These are three powerful diagnostic tools to understand the physical properties of the dust : the size, shape and composition of the dust particles. This can inform us on the population of parent bodies, also called planetesimals, which generate those particles through collisions. It is however very rare to be able to combine all those three observables for the same system, as this requires different high-contrast imaging techniques to suppress the starlight and reveal the faint scattered light emission from the dust. Due to its brightness, the ring detected around the A-type star HR 4796 is a notable exception, with both unpolarised and polarised images covering near-infrared wavelengths. Here, we show how measurements of dust particles in the laboratory can reproduce the observed near-infrared photo-polarimetric properties of the HR 4796 disc. Experimental characterisation of dust allows to bypass the current limitations of dust models to reproduce simultaneously the phase function, the degree of polarisation and the spectral reflectance.", "keyphrases": ["hr 4796", "light scattering", "debris disc", "cosmic dust"]}
{"id": "ogle2023radio", "title": "Radio Jet Feedback on the Inner Disk of Virgo Spiral Galaxy Messier 58", "abstract": "Spitzer spectral maps reveal a disk of highly luminous, warm (>150 K) H2 in the center of the massive spiral galaxy Messier 58, which hosts a radio-loud AGN. The inner 2.6 kpc of the galaxy appears to be overrun by shocks from the radio jet cocoon. Gemini NIRI imaging of the H2 1-0 S(1) emission line, ALMA CO 2-1, and HST multiband imagery indicate that much of the molecular gas is shocked in-situ, corresponding to lanes of dusty molecular gas that spiral towards the galaxy nucleus. The CO 2-1 and ionized gas kinematics are highly disturbed, with velocity dispersion up to 300 km/s. Dissipation of the associated kinetic energy and turbulence, likely injected into the ISM by radio-jet driven outflows, may power the observed molecular and ionized gas emission from the inner disk. The PAH fraction and composition in the inner disk appear to be normal, in spite of the jet and AGN activity. The PAH ratios are consistent with excitation by the interstellar radiation field from old stars in the bulge, with no contribution from star formation. The phenomenon of jet-shocked H2 may substantially reduce star formation and help to regulate the stellar mass of the inner disk and supermassive black hole in this otherwise normal spiral galaxy. Similarly strong H2 emission is found at the centers of several nearby spiral and lenticular galaxies with massive bulges and radio-loud AGN.", "keyphrases": ["active galactic nuclei", "radio jets", "shocks", "dust"]}
{"id": "russano2023eruptive", "title": "Eruptive events with exceptionally bright emission in HI Ly-alpha observed by the Metis coronagraph", "abstract": "Metis, the coronagraph on board Solar Orbiter, provides for the first time coronagraphic imaging in the ultraviolet HI Ly-alpha line and, simultaneously, in polarized visible light, thus providing a host of information on the properties of CMEs and solar eruptions like their overall dynamics, time evolution, mass content, and outflow propagation velocity in the expanding corona. We analyzed in this work six CMEs observed by Metis between April and October 2021, which are characterized by a very strong HI Ly-alpha emission. We studied in particular the morphology, kinematics, and the temporal and radial evolution of the emission of such events, focusing on the brightest UV features. The kinematics of the eruptive events under consideration were studied by determining the height-time profiles of the brightest parts on the Metis plane of the sky. Furthermore, the 3D position in the heliosphere of the CMEs were determined by employing co-temporal images from two other coronagraphs: LASCO/C2 onboard SOHO, and COR2 onboard STEREO-A. Finally, the radiometrically calibrated Metis images of the bright UV features were analyzed to provide estimates of their volume and density. From the kinematics and radiometric analyses, we obtained indications of the temperatures of the bright UV cores of these events. The analysis of these strong UV-emitting features associated with coronal mass ejections demonstrates the capabilities of the current constellation of space coronagraphs, Metis, LASCO/C2, and COR2, in providing a complete characterization of the structure and dynamics of eruptive events in their propagation phase from their inception up to several solar radii. Furthermore, we show how the unique capabilities of the Metis instrument to observe these events in both HI Ly-alpha line and polarized VL radiation allow plasma diagnostics on the thermal state of these events.", "keyphrases": ["corona", "atmosphere", "uv radiation", "coronal mass ejections (cmes)"]}
{"id": "purandardas2023peculiar", "title": "Peculiar abundances of the cool carbon star HE 1104-0957", "abstract": "We present, for the first time, a detailed abundance analysis of the carbon star HE 1104\u22120957 based on high resolution (R\u223c 50 000) spectra. Our analysis shows that the object is an extremely metal-poor star with [Fe/H] \u223c \u22122.96. We find that the object shows enhancement of carbon with [C/Fe] \u223c 1.82. However, it does not fall into any of the sub-groups of carbon-enhanced metal-poor (CEMP) stars based on the characteristic elemental abundance ratios used for the classification of various CEMP sub-groups. HE 1104\u22120957 is also found to exhibit an enhancement of oxygen and nitrogen with [O/Fe], and [N/Fe] \u223c 1.54, and 2.54 respectively. In HE 1104\u22120957, \u03b1-elements are found to be slightly enhanced with [\u03b1/Fe] \u223c 0.46. Fe-peak elements are also moderately enhanced in HE 1104\u22120957 with a value 0.63 with respect to Fe. Our analysis shows that HE 1104\u22120957 exhibits enhancement of neutron-capture elements, particularly r-process elements. The low-resolution spectra of this object shows the spectral features characteristics of a typical C-R star. However, We find that the surface chemical compositions of this object is contradictory to that expected for a C-R star. It requires a detailed analysis to better understand the abundance anomalies exhibited by this object.", "keyphrases": ["metal-poor stars", "abundances", "chemically peculiar", "nucleosynthesis"]}
{"id": "vasilyev2023detecting", "title": "Detecting stellar activity cycles in p-mode travel times: Proof of concept using SOHO/VIRGO solar observations", "abstract": "The eleven year solar cycle is known to affect the global modes of solar acoustic oscillations. In particular, p mode frequencies increase with solar activity. We propose a new method to detect the solar cycle from the p-mode autocorrelation function, and we validate this method using VIRGO/SPM photometric time series from solar cycles 23 and 24. The p-mode autocorrelation function shows multiple wavepackets separated by time lags of \u223c123 min. Using a one-parameter fitting method (from local helioseismology), we measure the seismic travel times from each wavepacket up to skip number 40. We find that the travel-time variations due to the solar cycle depend sensitively on the skip number, with the strongest signature in odd skips from 17 to 31. Taking the noise covariance into account, the travel-time perturbations can be averaged over all skip numbers to enhance the signal-to-noise ratio. This method is robust to noise, simpler to implement than peak bagging in the frequency domain, and is promising for asteroseismology. We estimate that the activity cycle of a Sun-like star should be detectable with this new method in Kepler-like observations down to a visual magnitude of mK\u223c11. However, for fainter stars, activity cycles are easier to detect in the photometric variability on rotational timescales.", "keyphrases": ["solar activity", "stellar activity", "helioseismology", "asteroseismology"]}
{"id": "derishev2023contemporaneous", "title": "The contemporaneous phase of GRB Afterglows \u2013 Application to GRB\u00a0221009A", "abstract": "The TeV observations of GRB\u00a0221009A provided us with a unique opportunity to analyze the contemporaneous phase in which both prompt and afterglow emissions are seen simultaneously. To describe this initial phase of Gamma-Ray Burst afterglows, we suggest a model for a blast wave with an intermittent energy supply. We treat the blast wave as a two-element structure. The central engine supplies energy to the inner part (shocked ejecta material) via the reverse shock. As the shocked ejecta material expands, its internal energy is transferred to the shocked external matter. We take into account the inertia of the shocked external material so that the pressure difference across this region determines the derivative of the blast wave's Lorentz factor. Applied to GRB\u00a0221009A, the model yields a very good fit to the observations of the entire TeV lightcurve except for three regions where there are excesses in the data with respect to the model. Those are well correlated with the three largest episodes of the prompt activity, and thus, we interpret them as the reverse shock emission. Our best-fit solution for GRB\u00a0221009A is an extremely narrow jet with an opening angle theta_j approx 0.07^o (500/\u0393_0) propagating into a wind-like external medium. This extremely narrow angle is consistent with the huge isotropic equivalent energy of this burst, and its inverse jet break explains the very rapid rise of the afterglow. Interestingly, photon-photon annihilation doesn't play a decisive role in the best-fit model.", "keyphrases": ["gamma-ray bursts", "non-thermal radiation sources", "relativistic jets", "shocks"]}
{"id": "beskin2023saint", "title": "SAINT (Small Aperture Imaging Network Telescope) \u2013 a wide-field telescope complex for detecting and studying optical transients at times from milliseconds to years", "abstract": "(Abridged) In this paper, we present a project of multi-channel wide-field optical sky monitoring system with high temporal resolution \u2013 Small Aperture Imaging Network Telescope (SAINT) \u2013 mostly built from off-the-shelf components and aimed towards searching and studying optical transient phenomena on the shortest time scales. The instrument consists of 12 channels each containing 30cm (F/1.5) objectives mounted on separate mounts with pointing speeds up to 50deg/s. Each channel is equipped with a 4128x4104 pixel, and a set of photometric griz filters and linear polarizers. At the heart of every channel is a custom built reducer-collimator module allowing rapid switching of an effective focal length of the telescope \u2013 due to it the system is capable to operate in either wide-field survey or narrow-field follow-up modes. In the first case, the field of view of the instrument is 470 square degrees and the detection limits (5\u03c3 level at 5500\u00c5) are 12.5-21 mag for exposure times of 20 ms - 20 min correspondingly. In the second, follow-up regime, all telescopes are oriented towards the single target, and SAINT becomes an equivalent to a 1m telescope, with the field of view reduced to 11\u2032 x 11\u2032, and the exposure times decreased down to 0.6 ms. Different channels may then have different filters installed, thus allowing a detailed study \u2013 acquiring both color and polarization information \u2013 of a target object with highest possible temporal resolution. The operation of SAINT will allow acquiring an unprecedented amount of data on various classes of astrophysical phenomena, from near-Earth to extragalactic ones, while its multi-channel design and the use of commercially available components allows easy expansion of its scale, and thus performance and detection capabilities.", "keyphrases": ["optical observations", "wide-field instruments", "photometry", "transients", "gamma-ray bursts", "fast radio bursts", "meteors", "red dwarfs", "white dwarfs"]}
{"id": "yu2023application", "title": "Application of Regularization Methods in the Sky Map Reconstruction of the Tianlai Cylinder Pathfinder Array", "abstract": "The Tianlai cylinder pathfinder is a radio interferometer array to test 21 cm intensity mapping techniques in the post-reionization era. It works in passive drift scan mode to survey the sky visible in the northern hemisphere. To deal with the large instantaneous field of view and the spherical sky, we decompose the drift scan data into m-modes, which are linearly related to the sky intensity. The sky map is reconstructed by solving the linear interferometer equations. Due to incomplete uv coverage of the interferometer baselines, this inverse problem is usually ill-posed, and regularization method is needed for its solution. In this paper, we use simulation to investigate two frequently used regularization methods, the Truncated Singular Value Decomposition (TSVD), and the Tikhonov regularization techniques. Choosing the regularization parameter is very important for its application. We employ the generalized cross validation (GCV) method and the L-curve method to determine the optimal value. We compare the resulting maps obtained with the different regularization methods, and for the different parameters derived using the different criteria. While both methods can yield good maps for a range of regularization parameters, in the Tikhonov method the suppression of noisy modes are more gradually applied, produce more smooth maps which avoids some visual artefacts in the maps generated with the TSVD method.", "keyphrases": ["radio interferometer", "map reconstruction", "inverse problem"]}
{"id": "kim2023spectroastrometry", "title": "Spectroastrometry and Imaging Science with Photonic Lanterns on Extremely Large Telescopes", "abstract": "Photonic lanterns (PLs) are tapered waveguides that gradually transition from a multi-mode fiber geometry to a bundle of single-mode fibers. In astronomical applications, PLs can efficiently couple multi-mode telescope light into a multi-mode fiber entrance and convert it into multiple single-mode beams. The output beams are highly stable and suitable for feeding into high-resolution spectrographs or photonic chip beam combiners. For instance, by using relative intensities in the output cores as a function of wavelength, PLs can enable spectroastrometry. In addition, by interfering beams in the output cores with a beam combiner in the backend, PLs can be used for high-throughput interferometric imaging. When used on an Extremely Large Telescope (ELT), with its increased sensitivity and angular resolution, the imaging and spectroastrometric capabilities of PLs will be extended to higher contrast and smaller angular scales. We study the potential spectroastrometry and imaging science cases of PLs on ELTs, including study of exomoons, broad-line regions of quasars, and inner circumstellar disks.", "keyphrases": ["photonic lantern", "spectroastrometry", "interferometric imaging", "high angular resolution", "high spectral resolution", "photonics"]}
{"id": "bjornsson2023modelling", "title": "Modelling of radio supernovae: Including the effects of inhomogeneities and radiative cooling", "abstract": "The presence of inhomogeneities in a spatially unresolved source is often hard to establish. This limits the accuracy with which the source properties can be determined. It is shown how observed features not expected for a homogeneous model can be used to infer the properties of the inhomogeneities in radio supernovae. Furthermore, the observed consequences of radiative cooling can be seriously affected by inhomogeneities. It is shown that the deduced source properties are very sensitive to the observed value of the cooling frequency; even a lower limit is often useful to constrain its characteristics. It is argued that the main synchrotron emission region in SN 2003L has a small volume filling factor, possibly as low as a few per cent. On the contrary, deviations from homogeneity are substantially smaller in SN 2002ap. The observed properties of type Ib/c radio supernovae in general indicate the volume filling factor to remain rather constant with time for individual sources but those peaking later at radio frequencies have lower filling factors. The conditions in the main synchrotron component in both SN 2003L and SN 2002ap are consistent with equipartition of energy between relativistic electrons and magnetic fields.", "keyphrases": ["supernovae", "inhomogeneities", "radiative cooling", "non-thermal radiation sources", "magnetic field"]}
{"id": "wang2023optical", "title": "An Optical Search for New Outbursting Low Mass X-Ray Binaries", "abstract": "Transient Low-Mass X-ray binaries (LMXBs) are discovered largely by X-ray and gamma-ray all-sky monitors. The X-ray outburst is also accompanied by an optical brightening, which empirically can precede detection of X-rays. Newly sensitive optical synoptic surveys may offer a complementary pathway for discovery, and potential for insight into the initial onset and propagation of the thermal instability that leads to the ionization of the accretion disk. We use the Zwicky Transient Facility (ZTF) alert stream to perform a comprehensive search at optical wavelengths for previously undiscovered outbursting LMXBs. Our pipeline first crossmatches the positions of the alerts to cataloged X-ray sources, and then analyzes the 30-day lightcurve of matched alerts by thresholding on differences with an 8-day exponentially weighted moving average. In addition to an nineteen month-long live search, we ran our pipeline over four years of ZTF archival data, recovering 4 known LMXBs. We also independently detected an outburst of MAXI J1957+032 in the live search and found the first outburst of Swift J1943.4+0228, an unclassified X-ray transient, in 10 years. Using Monte Carlo simulations of the Galactic LMXB population, we estimate that 29", "keyphrases": ["lmxbs", "x-ray binaries", "sky surveys"]}
{"id": "jafariyazani2023predicting", "title": "Predicting the Spectroscopic Features of Galaxies by Applying Manifold Learning on Their Broad-Band Colors: Proof of Concept and Potential Applications for Euclid, Roman, and Rubin LSST", "abstract": "Entering the era of large-scale galaxy surveys which will deliver unprecedented amounts of photometric and spectroscopic data, there is a growing need for more efficient, data driven, and less model-dependent techniques to analyze spectral energy distribution of galaxies. In this work, we demonstrate that by taking advantage of manifold learning approaches, we can estimate spectroscopic features of large samples of galaxies from their broadband photometry when spectroscopy is available only for a fraction of the sample. This will be done by applying the Self Organizing Map (SOM) algorithm on broadband colors of galaxies and mapping partially available spectroscopic information into the trained maps. In this pilot study, we focus on estimating 4000A break in a magnitude-limited sample of galaxies in the COSMOS field. We use observed galaxy colors (ugrizYJH) as well as spectroscopic measurements for a fraction of the sample from LEGA-C and zCOSMOS spectroscopic surveys to estimate this feature for our parent photometric sample. We recover the D4000 feature for galaxies which only have broadband colors with uncertainties about twice of the uncertainty of the employed spectroscopic surveys. Using these measurements we observe a positive correlation between D4000 and stellar mass of the galaxies in our sample with weaker D4000 features for higher redshift galaxies at fixed stellar masses. These can be explained with downsizing scenario for the formation of galaxies and the decrease in their specific star formation rate as well as the aging of their stellar populations over this time period.", "keyphrases": ["broad band photometry", "spectroscopy", "galaxy colors", "self organizing map"]}
{"id": "chornay2023probing", "title": "Probing the Local Planetary Nebula Luminosity Function with Gaia", "abstract": "The Planetary Nebula Luminosity Function (PNLF) remains an important extragalactic distance indicator despite a still limited understanding of its most important feature - the bright cut-off. External galaxies benefit from consistent distance and extinction, which makes determining the PNLF easier but detailed study of individual objects much more difficult. Now, the advent of parallaxes from the Gaia mission has dramatically improved distance estimates to planetary nebulae (PNe) in the Milky Way. We have acquired ground-based narrowband imagery and measured the [OIII] fluxes for a volume-limited sample of hundreds of PNe whose best distance estimates from Gaia parallaxes and statistical methods place them within 3 kpc of the Sun. We present the first results of our study, comparing the local PNLF to other galaxies with different formation histories, and discussing how the brightness of the PNe relates to the evolutionary state of their central stars and the properties of the nebula.", "keyphrases": ["planetary nebulae", "surveys", "distances"]}
{"id": "teixeira2023carbondeficient", "title": "The Carbon-Deficient Evolution of TRAPPIST-1c", "abstract": "Transiting planets orbiting M dwarfs provide the best opportunity to study the atmospheres of rocky planets with current facilities. As JWST enters its second year of science operations, an important initial endeavor is to determine whether these rocky planets have atmospheres at all. M dwarf host stars are thought to pose a major threat to planetary atmospheres due to their high magnetic activity over several billion-year timescales, and might completely strip atmospheres. Several Cycle 1 and 2 GO and GTO programs are testing this hypothesis, observing a series of rocky planets to determine whether they retained their atmospheres. A key case-study is TRAPPIST-1c, which receives almost the same bolometric flux as Venus. We might, therefore, expect TRAPPIST-1c to possess a thick, CO2-dominated atmosphere. Instead, Zieba et al. (2023) show that TRAPPIST-1c has little to no CO2 in its atmosphere. To interpret these results, we run coupled time-dependent simulations of planetary outgassing and atmospheric escape to model the evolution of TRAPPIST-1c's atmosphere. We find that the stellar wind stripping that is expected to occur on TRAPPIST-1c over its lifetime can only remove up to \u223c16 bar of CO2, less than the modern CO2 inventory of either Earth or Venus. Therefore, we infer that TRAPPIST-1c either formed volatile-poor, as compared to Earth and Venus, or lost a substantial amount of CO2 during an early phase of hydrodynamic hydrogen escape. Finally, we scale our results for the other TRAPPIST-1 planets, finding that the more distant TRAPPIST-1 planets may readily retain atmospheres.", "keyphrases": ["exoplanets", "atmospheres", "habitability", "trappist-1c"]}
{"id": "ray2023sagittarius", "title": "Sagittarius A^\u22c6 as a plausible source candidate for PeV neutrinos", "abstract": "We propose that the recently observed diffuse neutrinos by IceCube with energies above 1 PeV might have originated from Sagittarius A\u22c6 located in the galactic disk. This implies that the astrophysical settings of Sagittarius A\u22c6 need to accelerate hadronic cosmic rays to energies of \u223c100 PeV or more. Then, the hadronic emission scenario argues that this galactic neutrino source is also a PeV gamma-ray source. Recent observation of galactic diffuse PeV gamma-rays with energies \u223c1 PeV by Large High Altitude Air Shower Observatory has also advocated this conjecture. In the present paper, we demonstrate that if protons are accelerated to energies of \u223c100 PeV or more as reported by Osmanov et al. (Astrophys. J. 835 164:2017) in Sagittarius A\u22c6 environment, then they might generate PeV neutrinos and gamma rays through cosmic rays-gas/interstellar matter (e.g. pp) interactions. We estimate theoretically the diffuse neutrino flux due to back-to-back charged pion decays and the accompanying gamma-ray flux from neutral pion decays. These results suggest that a fraction (\u22431", "keyphrases": ["galactic center", "particle acceleration", "plasma motion", "neutrinos", "gamma rays"]}
{"id": "chen2023alma", "title": "ALMA High-resolution Spectral Survey of Thioformaldehyde (H2CS) Towards Massive Protoclusters", "abstract": "Investigating the temperature and density structures of gas in massive protoclusters is crucial for understanding the chemical properties therein. In this study, we present observations of the continuum and thioformaldehyde (H2CS) lines at 345 GHz of 11 massive protoclusters using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope. High spatial resolution and sensitivity observations have detected 145 continuum cores from the 11 sources. H2CS line transitions are observed in 72 out of 145 cores, including line-rich cores, warm cores and cold cores. The H2 column densities of the 72 cores are estimated from the continuum emission which are larger than the density threshold value for star formation, suggesting that H2CS can be widely distributed in star-forming cores with different physical environments. Rotation temperature and column density of H2CS are derived by use of the XCLASS software. The results show the H2CS abundances increase as temperature rises and higher gas temperatures are usually associated with higher H2CS column densities. The abundances of H2CS are positively correlated with its column density, suggesting that the H2CS abundances are enhanced from cold cores, warm cores to line-rich cores in star forming regions.", "keyphrases": ["astrochemistry", "line identification", "temperature", "abundance", "thioformaldehyde"]}
{"id": "miller2023composition", "title": "The composition of Saturn's rings", "abstract": "The origin and evolution of Saturn's rings is critical to understanding the Saturnian system as a whole. Here, we discuss the physical and chemical composition of the rings, as a foundation for evolutionary models described in subsequent chapters. We review the physical characteristics of the main rings, and summarize current constraints on their chemical composition. Radial trends are observed in temperature and to a limited extent in particle size distribution, with the C ring exhibiting higher temperatures and a larger population of small particles. The C ring also shows evidence for the greatest abundance of silicate material, perhaps indicative of formation from a rocky body. The C ring and Cassini Division have lower optical depths than the A and B rings, which contributes to the higher abundance of the exogenous neutral absorber in these regions. Overall, the main ring composition is strongly dominated by water ice, with minor silicate, UV absorber, and neutral absorber components. Sampling of the innermost D ring during Cassini's Grand Finale provides a new set of in situ constraints on the ring composition, and we explore ongoing work to understand the linkages between the main rings and the D ring. The D ring material is organic- and silicate-rich and water-poor relative to the main rings, with a large population of small grains. This composition may be explained in part by volatile losses in the D ring, and current constraints suggest some degree of fractionation rather than sampling of the bulk D ring material.", "keyphrases": ["ring particle composition", "mixing and particle size distribution", "ring radial and vertical structure", "d ring atmosphere"]}
{"id": "wang2023enhanced", "title": "Enhanced three-minute oscillation above a sunspot during a solar flare", "abstract": "Three-minute oscillations are a common phenomenon in the solar chromosphere above a sunspot. Oscillations can be affected by the energy release process related to solar flares. In this paper, we report on an enhanced oscillation in flare event SOL2012-07-05T21:42 with a period of around three minutes, that occurred at the location of a flare ribbon at a sunspot umbra-penumbra boundary, and was observed both in chromo-spheric and coronal passbands. An analysis of this oscillation was carried out using simultaneous ground-based observations from the Goode Solar Telescope (GST) at the Big Bear Solar Observatory (BBSO) and space-based observations from the Solar Dynamics Observatory (SDO). A frequency shift was observed before and after the flare, with the running penumbral wave that was present with a period of about 200 s before the flare co-existing with a strengthened oscillation with a period of 180 s at the same locations after the flare. We also found a phase difference between different passbands, with the oscillation occurring from high-temperature to low-temperature passbands. Theoretically, the change in frequency is strongly dependent on the variation of the inclination of the magnetic field and the chromospheric temperature. Following an analysis of the properties of the region, we find the frequency change is caused by the slight decrease of the magnetic inclination angle to the local vertical. In addition, we suggest that the enhanced three-minute oscillation is related to the additional heating, maybe due to the downflow, during the EUV late phase of the flare.", "keyphrases": ["flare", "flare ribbon", "he i 10830 a\u02da", "oscillation"]}
{"id": "siebert2023clues", "title": "Clues to PPN Chemical Evolution: The Unique Molecular Environment of V510 Pup", "abstract": "V510 Pup (IRAS 08005-2356) is a binary post-AGB system with a fast molecular outflow that has been noted for its puzzling mixture of carbon- and oxygen-rich features in the optical and infrared. To explore this chemical dichotomy and relate it to the kinematics of the source, we present an ACA spectral line survey detailing fourteen newly detected molecules in this pre-planetary nebula. The simultaneous presence of CN/C2H/HC3N and SO/SO2 support the previous conclusion of mixed chemistry, and their line profiles indicate that the C- and O-rich material trace distinct velocity structures in the outflow. This evidence suggests that V510 Pup could harbor a dense O-rich central waist from an earlier stage of evolution, which persisted after a fast C-rich molecular outflow formed. By studying the gas phase composition of this unique source, we aim to reveal new insights into the interplay between dynamics and chemistry in rapidly evolving post-AGB systems.", "keyphrases": ["stellar evolution", "circumstellar matter", "astrochemistry", "post-agb stars"]}
{"id": "zelko2023probing", "title": "Probing Dark Matter with Adaptive-optics based Flux Ratio Anomalies: Photometric and Astrometric Precision", "abstract": "Strong gravitational lensing is a powerful probe of the distribution of matter on sub-kpc scales. It can be used to test the existence of completely dark subhalos surrounding galaxies, as predicted by the standard cold dark matter model, or to test alternative dark matter models. The constraining power of the method depends strongly on photometric and astrometric precision and accuracy. We simulate and quantify the capabilities of upcoming adaptive optics systems and advanced instruments on ground-based telescopes, focusing as an illustration on the Keck Telescope (OSIRIS + KAPA, LIGER + KAPA) and the Thirty Meter Telescope (TMT; IRIS + NFIRAOS). We show that these new systems will achieve dramatic improvements over current ones in both photometric and astrometric precision. Narrow line flux ratio errors below 2", "keyphrases": ["dark matter", "strong gravitational lensing", "adaptive optics"]}
{"id": "palle2023groundbreaking", "title": "Ground-breaking Exoplanet Science with the ANDES spectrograph at the ELT", "abstract": "In the past decade the study of exoplanet atmospheres at high-spectral resolution, via transmission/emission spectroscopy and cross-correlation techniques for atomic/molecular mapping, has become a powerful and consolidated methodology. The current limitation is the signal-to-noise ratio during a planetary transit. This limitation will be overcome by ANDES, an optical and near-infrared high-resolution spectrograph for the ELT. ANDES will be a powerful transformational instrument for exoplanet science. It will enable the study of giant planet atmospheres, allowing not only an exquisite determination of atmospheric composition, but also the study of isotopic compositions, dynamics and weather patterns, mapping the planetary atmospheres and probing atmospheric formation and evolution models. The unprecedented angular resolution of ANDES, will also allow us to explore the initial conditions in which planets form in proto-planetary disks. The main science case of ANDES, however, is the study of small, rocky exoplanet atmospheres, including the potential for biomarker detections, and the ability to reach this science case is driving its instrumental design. Here we discuss our simulations and the observing strategies to achieve this specific science goal. Since ANDES will be operational at the same time as NASA's JWST and ESA's ARIEL missions, it will provide enormous synergies in the characterization of planetary atmospheres at high and low spectral resolution. Moreover, ANDES will be able to probe for the first time the atmospheres of several giant and small planets in reflected light. In particular, we show how ANDES will be able to unlock the reflected light atmospheric signal of a golden sample of nearby non-transiting habitable zone earth-sized planets within a few tenths of nights, a scientific objective that no other currently approved astronomical facility will be able to reach.", "keyphrases": ["andes", "elt", "exoplanets", "proto-planetary disks"]}
{"id": "pontoppidan2023highcontrast", "title": "High-contrast JWST-MIRI spectroscopy of planet-forming disks for the JDISC Survey", "abstract": "The JWST Disk Infrared Spectral Chemistry Survey (JDISCS) aims to understand the evolution of the chemistry of inner protoplanetary disks using the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST). With a growing sample of >30 disks, the survey implements a custom method to calibrate the MIRI Medium Resolution Spectrometer (MRS) to contrasts of better than 1:300 across its 4.9-28 micron spectral range. This is achieved using observations of Themis-family asteroids as precise empirical reference sources. High spectral contrast enables precise retrievals of physical parameters, searches for rare molecular species and isotopologues, and constraints on the inventories of carbon- and nitrogen-bearing species. JDISCS also offers significant improvements to the MRS wavelength and resolving power calibration. We describe the JDISCS calibrated data and demonstrate its quality using observations of the disk around the solar-mass young star FZ Tau. The FZ Tau MIRI spectrum is dominated by strong emission from warm water vapor. We show that the water and CO line emission originates from the disk surface and traces a range of gas temperatures of \u00a0500-1500 K. We retrieve parameters for the observed CO and H2O lines, and show that they are consistent with a radial distribution represented by two temperature components. A high water abundance of n(H2O)\u00a010^-4 fills the disk surface at least out to the 350 K isotherm at 1.5 au. We search the FZ Tau environs for extended emission detecting a large (radius of \u00a0300 au) ring of emission from H2 gas surrounding FZ Tau, and discuss its origin.", "keyphrases": ["protoplanetary disks", "astrochemistry", "water vapor", "infrared spectroscopy"]}
{"id": "lu2023stellar", "title": "Stellar Loci. VII. Photometric Metallicities of 5 Million FGK Stars Based on GALEX GR6+7 AIS and Gaia EDR3", "abstract": "We combine photometric data from GALEX GR6+7 AIS and Gaia EDR3 with stellar parameters from the SAGA and PASTEL catalogs to construct high-quality training samples for dwarfs (0.4<BP\u2212RP<1.6) and giants (0.6<BP\u2212RP<1.6). We apply careful reddening corrections using empirical temperature- and extinction-dependent extinction coefficients. Using the two samples, we establish a relationship between stellar loci (NUV\u2212BP vs. BP\u2212RP colors), metallicity, and MG. For a given BP\u2212RP color, a 1 dex change in [Fe/H] corresponds to an approximately 1 magnitude change in NUV\u2212BP color for solar-type stars. These relationships are employed to estimate metallicities based on NUV\u2212BP, BP\u2212RP, and MG. Thanks to the strong metallicity dependence in the GALEX NUV-band, our models enable a typical photometric-metallicity precision of approximately \u03c3[Fe/H] = 0.11 dex for dwarfs and \u03c3[Fe/H] = 0.17 dex for giants, with an effective metallicity range extending down to [Fe/H] =\u22123.0 for dwarfs and [Fe/H] =\u22124.0 for giants. We also find that the NUV-band based photometric-metallicity estimate is not as strongly affected by carbon enhancement as previous photometric techniques. With the Gaia and GALEX data, we have estimated metallicities for about 5 million stars across almost the entire sky, including approximately 4.5 million dwarfs and 0.5 million giants. This work demonstrates the potential of the NUV-band for estimating photometric metallicities, and sets the groundwork for utilizing the NUV data from space telescopes such as the upcoming Chinese Space Station Telescope.", "keyphrases": ["metallicity", "stellar fundamental parameters", "astronomy data analysis"]}
{"id": "glowacki2023hi", "title": "HI, FRB, what's your z: The first FRB host galaxy redshift from radio observations", "abstract": "Identification and follow up observations of the host galaxies of fast radio bursts (FRBs) not only help us understand the environments in which the FRB progenitors reside, but also provide a unique way of probing the cosmological parameters using the dispersion measures of FRBs and distances to their origin. A fundamental requirement is an accurate distance measurement to the FRB host galaxy, but for some sources viewed through the Galactic plane, optical/NIR spectroscopic redshifts are extremely difficult to obtain due to dust extinction. Here we report the first radio-based spectroscopic redshift measurement for an FRB host galaxy, through detection of its neutral hydrogen (HI) 21-cm emission using MeerKAT observations. We obtain an HI-based redshift of z = 0.0357 for the host galaxy of FRB 20230718A, an apparently non-repeating FRB detected in the CRAFT survey and localized at a Galactic latitude of -0.367 deg. Our observations also reveal that the FRB host galaxy is interacting with a nearby companion, which is evident from the detection of an HI bridge connecting the two galaxies. This result demonstrates the value of HI to obtain redshifts of FRBs at low Galactic latitudes and redshifts. Such nearby FRBs whose dispersion measures are dominated by the Milky Way can be used to characterise these components and thus better calibrate the remaining cosmological contribution to dispersion for more distant FRBs that provide a strong lever arm to examine the Macquart relation between cosmological DM and redshift.", "keyphrases": ["hi line emission", "fast radio bursts", "radio transient sources"]}
{"id": "dodorico2023galaxy", "title": "Galaxy Formation and Symbiotic Evolution with the Inter-Galactic Medium in the Age of ELT-ANDES", "abstract": "High-resolution absorption spectroscopy toward bright background sources has had a paramount role in understanding early galaxy formation, the evolution of the intergalactic medium and the reionisation of the Universe. However, these studies are now approaching the boundaries of what can be achieved at ground-based 8-10m class telescopes. The identification of primeval systems at the highest redshifts, within the reionisation epoch and even into the dark ages, and of the products of the first generation of stars and the chemical enrichment of the early Universe, requires observing very faint targets with a signal-to-noise ratio high enough to detect very faint spectral signatures. In this paper, we describe the giant leap forward that will be enabled by ANDES, the high-resolution spectrograph for the ELT, in these key science fields, together with a brief, non-exhaustive overview of other extragalactic research topics that will be pursued by this instrument, and its synergistic use with other facilities that will become available in the early 2030s.", "keyphrases": ["galaxy formation and evolution", "intergalactic medium", "circumgalactic medium", "interstellar medium", "high-resolution spectroscopy", "andes"]}
{"id": "maxted2023eblm", "title": "The EBLM Project \u2013 From False Positives to Benchmark Stars and Circumbinary Exoplanets", "abstract": "The EBLM project aims to characterise very low-mass stars that are companions to solar-type stars in eclipsing binaries. We describe the history and motivation for this project, the methodology we use to obtain precise mass, radius and effective temperature estimates for very low-mass M-dwarfs, and review results of the EBLM study and those from related projects. We show that radius inflation in fully-convective stars is a more subtle effect than was previously thought based on less precise measurements, i.e. the mass-radius-effective temperature relations we observe for fully-convective stars in single-line eclipsing binaries show reasonable agreement with theoretical models, particularly if we account for the M-dwarf metallicity, as inferred from the analysis of the primary star spectrum.", "keyphrases": ["eclipsing binary stars", "very low-mass stars", "fundamental properties of stars", "exoplanets"]}
{"id": "goudfrooij2023algorithm", "title": "An Algorithm to Mitigate Charge Migration Effects in Data from the Near Infrared Imager and Slitless Spectrograph on the James Webb Space Telescope", "abstract": "We present an algorithm that mitigates the effects of charge migration due to the \"brighter-fatter effect\u201d (BFE) that occurs for highly illuminated stars in the Teledyne HAWAII-2RG detectors used in the NIRCam, NIRISS, and NIRSpec science instruments aboard the James Webb Space Telescope (JWST). The impact of this effect is most significant for photometry and spectrophotometry of bright stars in data for which the point spread function (PSF) is undersampled, which is the case for several observing modes of the NIRISS instrument. The main impact of the BFE to NIRISS data is incorrect count rate determinations for pixels in the central regions of PSFs of bright stars due to jump detections that are caused by charge migration from peak pixels to surrounding pixels. The effect is especially significant for bright compact sources in resampled, distortion-free images produced by the drizzle algorithm: quantitatively, apparent flux losses of > 50", "keyphrases": ["astronomical instrumentation", "infrared observatories", "direct imaging", "astronomy data analysis"]}
{"id": "colosimo2023initial", "title": "Initial Characterization of the First Speedster-EXD550 Event-Driven X-Ray Hybrid CMOS Detectors", "abstract": "Future x-ray observatories will require imaging detectors with fast readout speeds that simultaneously achieve or exceed the other high performance parameters of x-ray charge-coupled devices (CCDs) used in many missions over the past three decades. Fast readout will reduce the impact of pile-up in missions with large collecting areas while also improving performance in other respects like timing resolution. Event-driven readout, in which only pixels with charge from x-ray events are read out, can be used to achieve these faster operating speeds. Speedster-EXD550 detectors are hybrid CMOS detectors (HCDs) capable of event-driven readout, developed by Teledyne Imaging Sensors and Penn State University. We present initial results from measurements of the first of these detectors, demonstrating their capabilities and performance in both full-frame and event-driven readout modes. These include dark current, read noise, gain variation, and energy resolution measurements from the first two engineering-grade devices.", "keyphrases": ["event-driven readout", "x-ray detector", "hybrid cmos", "complementary metal-oxide semiconductor", "x-ray astrophysics", "blackcat cubesat"]}
{"id": "latouf2023bayesian", "title": "Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) II: Using Grid-Based Nested Sampling in Coronagraphy Observation Simulations for O2 and O3", "abstract": "We present the results for the detectability of the O2 and O3 molecular species in the atmosphere of an Earth-like planet using reflected light at the visible wavelengths. By quantifying the detectability as a function of signal-to-noise ration (SNR), we can constrain the best methods to detect these biosignatures with nest-generation telescopes designed for high-contrast coronagraph. Using 25 bandpasses between 0.515 and 1 micron, and a pre-constructed grid of geometric albedo spectra, we examined the spectral sensitivity needed to detect these species for a range of molecular abundances. We first replicate a modern-Earth twin atmosphere to study the detectability of current O2 and O3 levels, and then expand to a wider range of literature-driven abundances for each molecule. We constrain the optimal 20", "keyphrases": ["planetary atmospheres", "telescopes", "methods: numerical", "techniques: nested sampling", "grids"]}
{"id": "lau2023look", "title": "A First Look with JWST Aperture Masking Interferometry (AMI): Resolving Circumstellar Dust around the Wolf-Rayet Binary WR 137 beyond the Rayleigh Limit", "abstract": "We present infrared aperture masking interferometry (AMI) observations of newly formed dust from the colliding winds of the massive binary system Wolf-Rayet (WR) 137 with JWST using the Near Infrared Imager and Slitless Spectrograph (NIRISS). NIRISS AMI observations of WR 137 and a point-spread-function calibrator star, HD\u00a0228337, were taken using the F380M and F480M filters in 2022 July and August as part of the Director's Discretionary Early Release Science (DD-ERS) program 1349. Interferometric observables (squared visibilities and closure phases) from the WR 137 \"interferogram\" were extracted and calibrated using three independent software tools: ImPlaneIA, AMICAL, and SAMpip. The analysis of the calibrated observables yielded consistent values except for slightly discrepant closure phases measured by ImPlaneIA. Based on all three sets of calibrated observables, images were reconstructed using three independent software tools: BSMEM, IRBis, and SQUEEZE. All reconstructed image combinations generated consistent images in both F380M and F480M filters. The reconstructed images of WR 137 reveal a bright central core with a \u223c300 mas linear filament extending to the northwest. A geometric colliding-wind model with dust production constrained to the orbital plane of the binary system and enhanced as the system approaches periapsis provided a general agreement with the interferometric observables and reconstructed images. Based on a colliding-wind dust condensation analysis, we suggest that dust formation within the orbital plane of WR 137 is induced by enhanced equatorial mass-loss from the rapidly rotating O9 companion star, whose axis of rotation is aligned with that of the orbit.", "keyphrases": ["massive stars", "wolf-rayet stars", "circumstellar dust"]}
{"id": "zhou2023exploring", "title": "Exploring primordial curvature perturbation on small scales with the lensing effect of fast radio bursts", "abstract": "Cosmological observations, e.g., cosmic microwave background, have precisely measured the spectrum of primordial curvature perturbation on larger scales, but smaller scales are still poorly constrained. Since primordial black holes (PBHs) could form in the very early Universe through the gravitational collapse of primordial density perturbations, constrains on the PBH could encodes much information on primordial fluctuations. In this work, we first derive a simple formula for lensing effect to apply PBH constraints with the monochromatic mass distribution to an extended mass distribution. Then, we investigate the latest fast radio burst observations with this relationship to constrain two kinds of primordial curvature perturbation models on the small scales. It suggests that, from the null search result of lensed fast radio burst in currently available observations, the amplitude of primordial curvature perturbation should be less than 8\u00d710\u22122 at the scale region of 105\u2212106 Mpc\u22121. This corresponds to an interesting mass range relating to binary black holes detected by LIGO-Virgo-KAGRA and future Einstein Telescope or Cosmic Explorer.", "keyphrases": ["primordial black holes", "gravitational lensing", "fast radio bursts"]}
{"id": "abaroa2023super", "title": "Super Winds and Radio Emission in X-ray Binary Systems", "abstract": "We have recently proposed that supercritical colliding wind binaries (SCWBs) are suitable scenarios for particle acceleration and nonthermal radiation. In these X-ray binary systems (XRBs), the wind from the companion star collides with the wind ejected from the super-Eddington accretion disk of the stellar black hole. Strong shocks are generated in this collision, leading to the acceleration of particles and subsequent broadband emission through different nonthermal radiative processes. In particular, we estimate luminosities of the order of L\u22481034ergs\u22121 in the radio band. One of the major components in these processes is the power provided by the super wind expelled from the disk. Furthermore, some properties of the wind photosphere, such as its geometry or its temperature distribution, also contribute to the absorption and reprocessing of the nonthermal radiation. In this work, we perform a more detailed description of the powerful wind launched from the accretion disk, in order to obtain a better understanding of the above-mentioned processes.", "keyphrases": ["x-ray binaries", "outflows", "black holes", "accretion disks"]}
{"id": "chworowsky2023evidence", "title": "Evidence for a Shallow Evolution in the Volume Densities of Massive Galaxies at z=4 to 8 from CEERS", "abstract": "We analyze the evolution of massive (log10 [M\u22c6/M\u2299] >10) galaxies at z\u223c 4\u20138 selected from the JWST Cosmic Evolution Early Release Science (CEERS) survey. We infer the physical properties of all galaxies in the CEERS NIRCam imaging through spectral energy distribution (SED) fitting with dense basis to select a sample of high redshift massive galaxies. Where available we include constraints from additional CEERS observing modes, including 18 sources with MIRI photometric coverage, and 28 sources with spectroscopic confirmations from NIRSpec or NIRCam wide-field slitless spectroscopy. We sample the recovered posteriors in stellar mass from SED fitting to infer the volume densities of massive galaxies across cosmic time, taking into consideration the potential for sample contamination by active galactic nuclei (AGN). We find that the evolving abundance of massive galaxies tracks expectations based on a constant baryon conversion efficiency in dark matter halos for z\u223c 1\u20134. At higher redshifts, we observe an excess abundance of massive galaxies relative to this simple model. These higher abundances can be explained by modest changes to star formation physics and/or the efficiencies with which star formation occurs in massive dark matter halos, and are not in tension with modern cosmology.", "keyphrases": ["galaxy evolution", "extragalactic astronomy", "galaxy formation"]}
{"id": "sha2023characterization", "title": "Characterization and Correction of the Scattering Background Produced by Dust on the Objective Lens of the Lijiang 10-cm Coronagraph", "abstract": "Scattered light from the objective lens, directly exposed to the intense sunlight, is a dominant source of stray light in internally occulted coronagraphs. The variable stray light, such as the scatter from dust on the objective lens, can produce varying scattering backgrounds in coronal images, significantly impacting image quality and data analysis. Using data acquired by the Lijiang 10-cm Coronagraph, the quantitative relationship between the distribution of dust on the objective lens and the resulting scattering backgrounds background is analyzed. Two empirical models for the scattering background are derived, and used to correct the raw coronal data. The second model, which depends on three parameters and performs better, shows that the scattering-background distribution varies with angle, weakens with increasing height, and enhances with increasing dust level on the objective lens. Moreover, we find that the dust on the center of the objective lens can contribute more significantly to the scattering background than on the edge. This study not only quantitatively confirms the significant impact of the stray light produced by dust on the objective lens of the coronagraph, but also corrects the coronal data with this stray light for the first time. Correcting for dust-scattered light is crucial for the high-precision calibration of ground-based coronagraph data, enabling a more accurate analysis of coronal structures. Furthermore, our model is envisioned to support the provision of reliable observational data for future routine coronal magnetic-field measurements using ground-based coronagraphs.", "keyphrases": ["corona", "coronagraph", "scatter", "stray light", "dust"]}
{"id": "boschetti2023cosmology", "title": "Towards cosmology with Void Lensing: how to find voids sensitive to weak-lensing and numerically interpret them", "abstract": "In this work, we present a study of the void lensing signal or the excess surface mass density (ESMD) around cosmic voids. First, we propose a new void-finder algorithm that is designed to capture the ESMD around voids. We compare our algorithm applied to projected slices with the ZOBOV void finder and find significantly deeper weak-lensing profiles for voids defined by our algorithm in the context of a realistic galaxy mock. Then we test the consistency between the measurements of the ESMD as measured through the shear of background galaxies and directly calculated through the dark matter density profiles of the same voids. We found inconsistencies for voids with diameter \u2265100h\u22121Mpc along the line-of-sight, but the consistency holds for smaller voids, meaning that we are indeed probing the underlying dark matter field by measuring the shear around these voids. Moreover, we show that voids found in the projected slices, which are highly sensitive to lensing, are correlated to 3D voids exhibiting intrinsic alignments between them.", "keyphrases": ["large scale structure", "cosmic voids", "weak leasing"]}
{"id": "divakar2023possibilities", "title": "Possibilities of Identifying Members from Milky Way Satellite Galaxies using Unsupervised Machine Learning Algorithms", "abstract": "A detailed study of stellar populations in Milky Way (MW) satellite galaxies remains an observational challenge due to their faintness and fewer spectroscopically confirmed member stars. We use unsupervised machine learning methods to identify new members for nine nearby MW satellite galaxies using Gaia data release-3 (Gaia DR3) astrometry and the Dark Energy Survey (DES) and the DECam Local Volume Exploration Survey (DELVE) photometry. Two density-based clustering algorithms, DBSCAN and HDBSCAN, have been used in the four-dimensional astrometric parameter space to identify member stars belonging to MW satellite galaxies. Our results indicate that we can recover more than 80", "keyphrases": ["machine learning", "clustering", "dbscan", "hdbscan", "milkyway satellite galaxies", "ultra faint dwarf galaxies"]}
{"id": "leboulleux2023challenges", "title": "Challenges and limitations of future exoplanet space imagers", "abstract": "The James Webb Space Telescope was not even launched yet when the Astro2020 Decadal Survey American report recommended the development of what is now called the Habitable World Observatory, also mentioned by the Voyage 2050 European report. This future space telescope, at 11 billions dollars and at least 6 m diameter, should allow, around 2040, the characterization of at least 25 exoplanets similar to Earth and orbiting around main sequence stars, with the hope of discovering one where life could have developed. This objective represents a technological challenge since it requires the design of spectro-imagers able to access very high contrasts (10^-8-10^-10) at low angular separations (smaller than 100 mas). This proceeding and the talk it is associated to address various obstacles that remain to be overcome in order to one day allow HabWorld to reach its ultimate performance.", "keyphrases": ["exoplanets", "habitable world observatory", "habworld", "instrumentation", "high-contrast imaging"]}
{"id": "velmani2023selfsimilar", "title": "A self-similar model of galaxy formation and dark halo relaxation", "abstract": "We develop a spherical self-similar model for the formation of a galaxy through gas collapsing in an isolated self-gravitating dark matter halo. We improve upon the existing literature on self-similar collapse in two ways. First, we include the effects of radiative cooling and the formation of a pseudo-disk at the center of collapse, in a parametrised manner. More importantly, for the first time we solve for the evolution of gas and dark matter simultaneously and self-consistently using a novel iterative approach. As a result, our model produces shell trajectories of both gas and dark matter that qualitatively agree with the results of full hydrodynamical simulations. We discuss the impact of various ingredients such as the accretion rate, gas equation of state, disk radius and cooling rate amplitude on the evolution of the gas shells. The self-consistent evolution of gas and dark matter allows us to study the response of the dark matter trajectories to the presence of collapsing gas, an effect that has gained increasing importance recently in the context of precision estimates of small-scale statistics like the matter power spectrum. Our default configuration produces a relaxation relation in qualitative agreement with that seen in cosmological hydrodynamical simulations, and further allows us to easily study the impact of the model ingredients mentioned above. As an initial application, we vary one ingredient at a time and find that the accretion rate and gas equation of state have the largest impact on the relaxation relation, while the cooling amplitude plays only a minor role. Our model thus provides a convenient framework to rapidly explore the coupled nonlinear impact of multiple astrophysical processes on the mass and velocity profiles of dark matter in galactic halos", "keyphrases": ["galaxy formation", "semi-analytic modeling", "dark matter simulations"]}
{"id": "jain2023coronal", "title": "Coronal dimmings as indicators of early CME propagation direction", "abstract": "Coronal mass ejections (CMEs) are solar eruptions of plasma and magnetic fields that significantly impact Space Weather, causing disruptions in technological systems and potential damage to power grids when directed towards Earth. Traditional coronagraphs along the Sun-Earth line struggle to precisely track the early evolution of Earth-directed CMEs. Coronal dimmings, localized reductions in extreme-ultraviolet (EUV) and soft X-ray emissions, are key indicators of CMEs in the low corona, resulting from mass loss and expansion during the eruption. This study introduces a novel method, DIRECD (Dimming InfeRred Estimate of CME Direction), to estimate the early propagation direction of CMEs based on the expansion of coronal dimmings. The approach involves 3D simulations of CMEs using a geometric cone model, exploring parameters like width, height, source location, and deflection from the radial direction. The dominant direction of dimming evolution is then determined, and an inverse problem is solved to reconstruct an ensemble of CME cones at various heights, widths, and deflections. By comparing the CME orthogonal projections onto the solar sphere with the dimming geometry, the 3D CME direction is derived.Validated through case studies on October 1, 2011, and September 6, 2011, the DIRECD method reveals the early propagation directions of CMEs. The CME on October 1, 2011, predominantly expands towards the South-East, while the CME on September 6, 2011, inclines towards the North-West. These findings align with previous studies using multi-viewpoint coronagraphic observations. The study demonstrates the utility of coronal dimming information for early CME direction estimation, providing valuable data for space weather forecasting and mitigating potential adverse impacts on Earth before observation in coronographs' field-of-view.", "keyphrases": ["sun", "dimmings", "solar activity", "coronal mass ejections"]}
{"id": "tricco2023smoothed", "title": "Smoothed particle magnetohydrodynamics", "abstract": "Smoothed particle magnetohydrodynamics has reached a level of maturity that enables the study of a wide range of astrophysical problems. In this review, the numerical details of the modern SPMHD method are described. The three fundamental components of SPMHD are methods to evolve the magnetic field in time, calculate accelerations from the magnetic field, and maintain the divergence-free constraint on the magnetic field (no monopoles). The connection between these three requirements in SPMHD will be highlighted throughout. The focus of this review is on the methods that work well in practice, with discussion on why they work well and other approaches do not. Numerical instabilities will be discussed, as well as strategies to overcome them. The inclusion of non-ideal MHD effects will be presented. A prospective outlook on possible avenues for further improvements will be discussed.", "keyphrases": ["smoothed particle magnetohydrodynamics", "smoothed particle hydrodynamics", "magnetohydrodynamics (mhd)", "lagrangian particle methods", "non-ideal mhd", "divergence cleaning", "astrophysics"]}
{"id": "despali2023gravitational", "title": "Gravitational lenses in hydrodynamical simulations", "abstract": "The gravitational lensing signal produced by a galaxy or a galaxy cluster is determined by its total matter distribution, providing us with a way to directly constrain their dark matter content. State-of-the-art numerical simulations successfully reproduce many observed properties of galaxies and can be used as a source of mock observations and predictions. Many gravitational lensing studies aim at constraining the nature of dark matter, discriminating between cold dark matter and alternative models. However, many past results are based on the comparison to simulations that did not include baryonic physics. Here we show that the presence of baryons can significantly alter the predictions: we look at the structural properties (profiles and shapes) of elliptical galaxies and at the inner density slope of subhaloes. Our results demonstrate that future simulations must model the interplay between baryons and alternative dark matter, to generate realistic predictions that could significantly modify the current constraints.", "keyphrases": ["strong lensing", "cosmology", "dark matter", "numerical simulations"]}
{"id": "verde2023tale", "title": "A tale of many H_0", "abstract": "The Hubble parameter H0, is not a univocally-defined quantity: it relates redshifts to distances in the near Universe, but is also a key parameter of the \u039bCDM standard cosmological model. As such, H0 affects several physical processes at different cosmic epochs, and multiple observables. We have counted more than a dozen H0's which are expected to agree if a) there are no significant systematics in the data and their interpretation and b) the adopted cosmological model is correct. With few exceptions (proverbially confirming the rule) these determinations do not agree at high statistical significance; their values cluster around two camps: the low (68 km/s/Mpc) and high (73 km/s/Mpc) camp. It appears to be a matter of anchors: the shape of the Universe expansion history agrees with the model, it is the normalizations that disagree. Beyond systematics in the data/analysis, if the model is incorrect there are only two viable ways to \"fix\" it: by changing the early time (z\u22731100) physics and thus the early time normalization, or by a global modification, possibly touching the model's fundamental assumptions (e.g., homogeneity, isotropy, gravity). None of these three options has the consensus of the community. The research community has been actively looking for deviations from \u039bCDM for two decades; the one we might have found makes us wish we could put the genie back in the bottle.", "keyphrases": ["cosmology", "cosmological parameters", "hubble parameter", "cosmological distances", "cosmic microwave background", "large-scale structure"]}
{"id": "chandra2023discovery", "title": "Discovery of torque reversal in the Be/X-ray binary pulsar GX 304-1", "abstract": "We study the long-term spin period evolution of the Be/X-ray binary pulsar GX 304-1 and discover a new torque reversal after nearly three years of spinning up. The averaged spin-up rate before the torque reversal is \u223c1.3\u00d710\u221213 Hz s\u22121 which changes to an averaged spin-down rate of \u223c\u22125\u00d710\u221214 Hz s\u22121. The pulsar is detected at low luminosities (about 2\u00d71035 erg s\u22121) near periastron passages during the torque reversal suggesting that accretion is not quenched during this period. The long-term optical observations of the companion star suggest that the activity of the companion star may have decreased compared to the period when X-ray outbursts were earlier detected from the pulsar. The spin-up rates estimated during regular bright outbursts of the pulsar are observed to decrease systematically as the pulsar enters a low activity state after the outbursts and undergoes torque reversal. We explore plausible mechanisms to explain the torque reversal and long-term spin-down in this pulsar.", "keyphrases": ["gx 304-1", "x-ray pulsar", "hmxb", "spin-up", "spin-down", "accretion torque", "x-ray binary"]}
{"id": "cao2023forecast", "title": "Forecast of joint analysis of cosmic shear and supernovae magnification from CSST and LSST", "abstract": "Cosmic shear and cosmic magnification reflect the same gravitational lensing field. Each of these two probes are affected by different systematics. We study the auto- and cross-correlations of the cosmic shear from the China Space Survey Telescope (CSST) and cosmic magnification of supernovae from Large Synoptic Survey Telescope (LSST). We want to answer, to what extent, by adding the magnification data we can remove the systematic bias in cosmic shear measurement. We generate the mock shear/magnification maps based on the correlation between of different tomographic bins. After obtaining the corrected power spectra, we adopt the Markov Chain Monte Carlo (MCMC) technique to fit the theoretical models, and investigate the constraints on the cosmological and nuisance parameters. We find that the with only cosmic shear data, there are 1\u03c3 bias in \u03c38 and intrinsic alignment model parameters. By adding the magnification data, we are able to remove these biases perfectly.", "keyphrases": ["cosmology", "weak lensing", "supernovae", "cosmic shear"]}
{"id": "titarchuk2023distinguish", "title": "How to distinguish white dwarf and neutron star X-ray binaries during their X-ray outbursts?", "abstract": "Neutron stars (NSs) and white dwarfs (WDs) are characterized by different geometric and physical properties, but their observed properties are often similar, making them difficult to distinguish. Therefore, it is desirable to search for their spectral features that could be easily identified from observations. We present spectral and timing signatures of NSs and WDs hosted in accreting X-ray binaries that can be easily identified from X-ray observations. We perform spectral and timing analysis of 4U\u00a01636\u201353 and SS\u00a0Cygni, as typical representatives of such NS and WD binaries, based on their X-ray observations by RXTE, ASCA, Suzaku and BeppoSAX uising Comptonization spectral model. As a result, we formulate a criterion that makes it easy to distinguish NS from WD in such binaries: NS X-rays exhibits clear quasi-stable behavior with the index \u0393\u21922 and is characterized by quasi periodic oscillations (QPOs) at \u03bdQPO>0.5\u00a0Hz, although WD X-rays is stable with \u0393\u21921.85 and is accompanied by QPOs at \u03bdQPO<0.05\u00a0Hz during source outbursts. In addition, we revealed that in 4U\u00a01636\u201353 the mHz QPOs anti-correlate with the plasma temperature, Te of Compton cloud (or the corona around a NS. This allowed us to associate mHz-QPOs with the corona dynamics during outburst cycle. The above index effect, now well established for 4U\u00a01636\u201353 and SS\u00a0Cygni using extensive observations, has previously been found in other low-mass X-ray NS and WD binaries and agrees well with the criterion for distinguishing NSs and WDs presented here.", "keyphrases": ["accretion", "accretion disks", "neutron star physics", "radiation mechanisms", "white dwarf physics"]}
{"id": "lange2023need", "title": "The need for spatially resolved observations of PAHs in protoplanetary discs", "abstract": "The signatures of polycyclic aromatic hydrocarbons (PAHs) have been observed in protoplanetary discs, and their emission features obtained from spectral energy distributions (SED) have been used in the literature to characterise their size and determine their abundance. Two simple disc models (uniform PAH distribution against a PAH gap in the inner disc) are compared to investigate the difference of their SED and obtainable information. We used the radiative transfer code RADMC-3D to model the SED of two protoplanetary discs orbiting a typical Herbig star, one of which features a depletion of PAHs in the inner disc. We further created artificial images of the discs at face-on view to extract radial profiles of the PAH emission in the infrared. We find that the extracted PAH features from an SED provide limited information about the PAHs in protoplanetary disc environments, except for the ionisation state. The distribution of PAHs in a protoplanetary disc influences the total observed PAH luminosity in a non-linear fashion and alters the relative strength between the 3.3 \u03bcm and 11.3 \u03bcm features. Furthermore, we produced radial profiles at the 3 \u03bcm, 6 \u03bcm and, 11 \u03bcm PAH emission features and find that they follow a double power-law profile where the slope reflects the radiative environment (single photon regime vs. multi-photon regime) in which the PAHs lie. Using spatially resolved techniques such as IFU or imaging in the era of the James Webb Space Telescope, we find that multi-wavelength radial emission profiles will not only provide information on the spatial distribution of the PAHs, but may also provide information on their size and underlying UV environment, which is crucial for photo-evaporative disc wind models.", "keyphrases": ["protoplanetary discs", "astrochemistry", "herbig ae/be stars"]}
{"id": "strugarek2023dynamics", "title": "Dynamics of the tachocline", "abstract": "The solar tachocline is an internal region of the Sun possessing strong radial and latitudinal shears straddling the base of the convective envelope. Based on helioseismic inversions, the tachocline is known to be thin (less than 5% of the solar radius). Since the first theory of the solar tachocline in 1992, this thinness has not ceased to puzzle solar physicists. In this review, we lay out the grounds of our understanding of this fascinating region of the solar interior. We detail the various physical mechanisms at stake in the solar tachocline, and put a particular focus on the mechanisms that have been proposed to explain its thinness. We also examine the full range of MHD processes including waves and instabilies that are likely to occur in the tachocline, as well as their possible connection with active region patterns observed at the surface. We reflect on the most recent findings for each of them, and highlight the physical understanding that is still missing and that would allow the research community to understand, in a generic sense, how the solar tachocline and stellar tachocline are formed, are sustained, and evolve on secular timescales.", "keyphrases": ["solar tachocline", "magnetohydrodynamics of stars", "shear and magnetic instabilities", "solar dynamo"]}
{"id": "liu2023spatially", "title": "A Spatially resolved X-ray Polarization map of the Vela Pulsar Wind Nebula", "abstract": "In this paper, we present a full spatially resolved polarization map for the Vela Pulsar Wind Nebula (PWN) observed by IXPE. By employing effective background discrimination techniques, our results show a remarkably high degree of local polarization in the outskirt region, exceeding 60", "keyphrases": ["pulsar wind nebulae", "magnetic fields", "polarimetry"]}
{"id": "disalvo2023low", "title": "Low Magnetic-Field Neutron Stars in X-ray Binaries", "abstract": "In this chapter we give an overview of the properties of X-ray binary systems containing a weakly magnetized neutron star. These are old (Giga-years life-time) semi-detached binary systems containing a neutron star with a relatively weak magnetic field (less than \u223c1010 Gauss) and a low-mass (less than 1M\u2299) companion star orbiting around the common center of mass in a tight system, with orbital period usually less than 1 day. The companion star usually fills its Roche lobe and transfers mass to the neutron star through an accretion disk, where most of the initial potential energy of the in-falling matter is released, reaching temperatures of tens of million Kelvin degrees, and therefore emitting most of the energy in the X-ray band. Their emission is characterized by a fast-time variability, possibly related to the short timescales in the innermost part of the system. Because of the weak magnetic field, the accretion flow can approach the neutron star until it is accreted onto its surface sometimes producing spectacular explosions known as type-I X-ray bursts. In some sources, the weak magnetic field of the neutron star (\u223c108\u2212109 Gauss) is strong enough to channel the accretion flow onto the polar caps, modulating the X-ray emission and revealing the fast rotation of the neutron star at millisecond periods. These systems are important for studies of fundamental physics, and in particular for test of Relativity and alternative theories of Gravity and for studies of the equation of state of ultra-dense matter, which are among the most important goals of modern physics and astrophysics.", "keyphrases": ["neutron stars", "low magnetic field", "x-ray binaries", "x-ray pulsars", "millisecond x-ray pulsars", "transitional pulsars", "fast variability", "type-i bursts", "burst oscillations", "x-ray spectra", "high-inclination sources", "very faint x-ray sources"]}
{"id": "libralato2023highprecision", "title": "High-precision astrometry and photometry with the JWST/MIRI imager", "abstract": "Astrometry is one of the main pillars of astronomy, and one of its oldest branches. Over the years, an increasing number of astrometric works by means of Hubble Space Telescope (HST) data have revolutionized our understanding of various phenomena. With the launch of JWST, it becomes almost instinctive to want to replicate or improve these results with data taken with the newest, state-of-the-art, space-based telescope. In this regard, the initial focus of the community has been on the Near-Infrared (NIR) detectors on board of JWST because of their high spatial resolution. This paper begins the effort to capture and apply what has been learned from HST to the Mid-InfraRed Instrument (MIRI) of JWST by developing the tools to obtain high-precision astrometry and photometry with its imager. We describe in detail how to create accurate effective point-spread-function (ePSF) models and geometric-distortion corrections, analyze their temporal stability, and test their quality to the extent of what is currently possible with the available data in the JWST MAST archive. We show that careful data reduction provides deep insight on the performance and intricacies of the MIRI imager, and of JWST in general. In an effort to help the community to devise new observing programs, we make our ePSF models and geometric-distortion corrections publicly available.", "keyphrases": ["astrometry", "photometry", "proper motions", "large magellanic cloud"]}
{"id": "unger2023coherent", "title": "The Coherent Magnetic Field of the Milky Way", "abstract": "We present a suite of models of the coherent magnetic field of the Galaxy (GMF) based on new divergence-free parametric functions describing the global structure of the field. The model parameters are fit to the latest full-sky Faraday rotation measures of extragalactic sources (RMs) and polarized synchrotron intensity maps from WMAP and Planck (PI), employing multiple models for the density of thermal and cosmic-ray electrons in the Galaxy. The robustness of the inferred properties of the GMF is gauged by studying many combinations of parametric field models and electron density models. We determine the pitch angle of the local magnetic field (11+/-1 deg.), explore the evidence for a grand-design spiral coherent magnetic field (inconclusive), determine the strength of the toroidal magnetic halo below and above the disk (same within 10", "keyphrases": ["galactic magnetic field", "galactic physics", "milky way", "cosmic rays"]}
{"id": "carleo2023gaps", "title": "The GAPS Programme at TNG L \u2013 TOI-4515 b: An eccentric warm Jupiter orbiting a 1.2 Gyr-old G-star", "abstract": "Context. Different theories have been developed to explain the origins and properties of close-in giant planets, but none of them alone can explain all of the properties of the warm Jupiters (WJs, Porb = 10 - 200 days). One of the most intriguing characteristics of WJs is that they have a wide range of orbital eccentricities, challenging our understanding of their formation and evolution. Aims. The investigation of these systems is crucial in order to put constraints on formation and evolution theories. TESS is providing a significant sample of transiting WJs around stars bright enough to allow spectroscopic follow-up studies. Methods. We carried out a radial velocity (RV) follow-up study of the TESS candidate TOI-4515 b with the high-resolution spectrograph HARPS-N in the context of the GAPS project, the aim of which is to characterize young giant planets, and the TRES and FEROS spectrographs. We then performed a joint analysis of the HARPS-N, TRES, FEROS, and TESS data in order to fully characterize this planetary system. Results. We find that TOI-4515 b orbits a 1.2 Gyr-old G-star, has an orbital period of Pb = 15.266446 +- 0.000013 days, a mass of Mb = 2.01 +- 0.05 MJ, and a radius of Rb = 1.09 +- 0.04 RJ. We also find an eccentricity of e = 0.46 +- 0.01, placing this planet among the WJs with highly eccentric orbits. As no additional companion has been detected, this high eccentricity might be the consequence of past violent scattering events.", "keyphrases": ["young exoplanets", "warm jupiters", "transit technique", "radial velocity technique"]}
{"id": "donkov2023thermodynamics", "title": "Thermodynamics of fluid elements in the context of saturated isothermal turbulence in molecular clouds", "abstract": "The presented paper is an attempt to investigate the dynamical states of an hydrodynamical isothermal turbulent self-gravitating system using some powerful tools of the classical thermodynamics. Our main assumption, inspired by the work of Keto et al. (2020), is that turbulent kinetic energy can be substituted for the macro-temperature of chaotic motion of fluid elements. As a proper sample for our system we use a model of turbulent self-gravitating isothermal molecular cloud which is at final stages of its life-cycle, when the dynamics is nearly in steady state. Starting from this point, we write down the internal energy for a physically small cloud's volume, and then using the first principle of thermodynamics obtain in explicit form the entropy, free energy, and Gibbs potential for this volume. Setting fiducial boundary conditions for the latter system (small volume) we explore its stability as a grand canonical ensemble. Searching for extrema of the Gibbs potential we obtain conditions for its minimum, which corresponds to a stable dynamical state of hydrodynamical system. This result demonstrates the ability of our novel approach.", "keyphrases": ["thermodynamics", "hydrodynamics", "stability", "molecular clouds"]}
{"id": "yutani2023apparent", "title": "Apparent effect of dust extinction on the observed outflow velocity of ionized gas in galaxy mergers", "abstract": "In this study, we examine photoionization outflows during the late stages of galaxy mergers, with a specific focus on the relation between observed velocity of outflowing gas and the apparent effects of dust extinction. We used the N-body/smoothed particle hydrodynamics (SPH) code ASURA for galaxy merger simulations. These simulations concentrated on identical galaxy mergers featuring supermassive black holes (SMBHs) of 108 M\u2299 and gas fractions of 30% and 10 %. From the simulation data, we derived velocity and velocity dispersion diagrams for the AGN-driven ionized outflowing gas. Our findings show that high-velocity outflows with velocity dispersions of 500 km s\u22121 or greater can be observed in the late stages of galactic mergers. Particularly, in buried AGNs, both the luminosity-weighted outflow velocity and velocity dispersion increase owing to the apparent effects of dust extinction. Owing to these effects, the velocity\u2013velocity dispersion diagrams display a noticeable blue-shifted tilt in models with higher gas fractions. Crucially, this tilt is not influenced by the AGN luminosity but emerges from the observational impacts of dust extinction. Our results imply that the observed high-velocity outflow exceeding 1000 km s\u22121 in buried AGNs may be linked to the dust extinction that occurs during the late stages of gas-rich galaxy mergers.", "keyphrases": ["supermassive black holes", "galaxy mergers", "active galaxies", "active galactic nuclei", "n-body simulations", "hydrodynamical simulations"]}
{"id": "leahy2023interpretation", "title": "On the Interpretation of XSPEC Abundances and Emission Measures", "abstract": "The purpose of this work is to describe the assumptions built into the X-ray spectrum fitting software XSPEC for the calculation of element abundances and emission measure of a plasma and to describe the effects when those assumptions are not accurate. The ratio of electron density to hydrogen density in XSPEC is fixed at a constant. The correct ratio can be calculated from the ionization states of the elements. We show the constant value used in XSPEC is valid to within 3.5", "keyphrases": ["emission measure", "supernova remnants", "abundances", "nucleosynthesis", "nuclear reactions"]}
{"id": "guglielmetti2023brain", "title": "A BRAIN study to tackle image analysis with artificial intelligence in the ALMA 2030 era", "abstract": "An ESO internal ALMA development study, BRAIN, is addressing the ill-posed inverse problem of synthesis image analysis employing astrostatistics and astroinformatics. These emerging fields of research offer interdisciplinary approaches at the intersection of observational astronomy, statistics, algorithm development, and data science. In this study, we provide evidence of the benefits of employing these approaches to ALMA imaging for operational and scientific purposes. We show the potential of two techniques, RESOLVE and DeepFocus, applied to ALMA calibrated science data. Significant advantages are provided with the prospect to improve the quality and completeness of the data products stored in the science archive and overall processing time for operations. Both approaches evidence the logical pathway to address the incoming revolution in data rates dictated by the planned electronic upgrades. Moreover, we bring to the community additional products through a new package, ALMASim, to promote advancements in these fields, providing a refined ALMA simulator usable by a large community for training and/or testing new algorithms.", "keyphrases": ["inverse problems", "inference methods", "bayesian probability theory", "machine learning", "image analysis", "radio astronomy"]}
{"id": "aravind2023optical", "title": "Optical spectroscopy of comets", "abstract": "Comets are pristine remnants of the Solar system, composed of dust and ice. They remain inactive and undetectable for most of their orbit due to low temperatures. However, as they approach the Sun, volatile materials sublimate, expelling dust and creating a visible coma. Spectroscopic observations of comets help the simultaneous study of both the gas emissions and reflected sunlight from dust particles. By implementing a long slit, the spatial variations in molecular emissions can be analysed to be further used for other computations. Additionally, spatial information aids in extracting the characteristic profile of the Af(rho) parameter, revealing insights into the behaviour of dust emissions. A sufficiently long slit would prove advantageous in extracting information about the emissions occurring at different parts of the coma or even the tail. We can gain an overall comprehensive understanding of a comet's chemical composition and dust emission by constructively utilising low-resolution spectroscopy with the help of a long slit.", "keyphrases": ["solar system minor bodies", "comet", "optical spectroscopy"]}
{"id": "sappey2023calibration", "title": "Calibration Unit Design for High-Resolution Infrared Spectrograph for Exoplanet Characterization (HISPEC)", "abstract": "The latest generation of high-resolution spectrograph instruments on 10m-class telescopes continue to pursue challenging science cases. Consequently, ever more precise calibration methods are necessary to enable trail-blazing science methodology. We present the High-resolution Infrared SPectrograph for Exoplanet Characterization (HISPEC) Calibration Unit (CAL), designed to facilitate challenging science cases such as Doppler imaging of exoplanet atmospheres, precision radial velocity, and high-contrast high-resolution spectroscopy of nearby exoplanets. CAL builds upon the heritage from the pathfinder instrument Keck Planet Imager and Characterizer (KPIC) and utilizes four near-infrared (NIR) light sources encoded with wavelength information that are coupled into single-mode fibers. They can be used synchronously during science observations or asynchronously during daytime calibrations. A hollow cathode lamp (HCL) and a series of gas absorption cells provide absolute calibration from 0.98 \u03bcm to 2.5 \u03bcm. A laser frequency comb (LFC) provides stable, time-independent wavelength information during observation and CAL implements a lower finesse astro-etalon as a backup for the LFC. Design lessons from instrumentation like HISPEC will serve to inform the requirements for similar instruments for the ELTs in the future.", "keyphrases": ["high-resolution spectroscopy", "astronomical instrumentation", "calibration", "precision radial velocity"]}
{"id": "matilsky2023confinement", "title": "Confinement of the Solar Tachocline by a Non-Axisymmetric Dynamo", "abstract": "We recently presented the first 3D numerical simulation of the solar interior for which tachocline confinement was achieved by a dynamo-generated magnetic field. In this followup study, we analyze the degree of confinement as the magnetic field strength changes (controlled by varying the magnetic Prandtl number) in a coupled radiative zone (RZ) and convection zone (CZ) system. We broadly find three solution regimes, corresponding to weak, medium, and strong dynamo magnetic field strengths. In the weak-field regime, the large-scale magnetic field is mostly axisymmetric with regular, periodic polarity reversals (reminiscent of the observed solar cycle), but fails to create a confined tachocline. In the strong-field regime, the large-scale field is mostly non-axisymmetric with irregular, quasi-periodic polarity reversals, and creates a confined tachocline. In the medium-field regime, the large-scale field resembles a strong-field dynamo for extended intervals, but intermittently weakens to allow temporary epochs of strong differential rotation. In all regimes, the amplitude of poloidal field strength in the RZ is very well explained by skin-depth arguments, wherein the oscillating field that gives rise to the skin depth (in the medium- and strong-field cases) is a non-axisymmetric field structure rotating with respect to the RZ. These new simulations reaffirm that tachocline confinement by the solar dynamo (the so-called fast magnetic confinement scenario) is possible, but suggest a new picture in which non-axisymmetric field components rotating with respect to the RZ play the primary role, instead of the regularly reversing axisymmetic field associated with the 22-year cycle.", "keyphrases": ["solar dynamo", "solar differential rotation", "solar interior", "solar radiative zone", "solar convective zone"]}
{"id": "goswami2023potential", "title": "On the potential of Carbon-Enhanced Metal-Poor stars for Galactic Archaeology", "abstract": "The low-mass metal-poor stars in the Galaxy that preserve in their atmosphere, the chemical imprints of the gas clouds from which they were formed can be used as probes to get insight into the origin and evolution of elements in the early galaxy, early star formation and nucleosynthesis. Among the metal-poor stars, a large fraction, the so-called carbon-enhanced metal-poor (CEMP) stars exhibits high abundance of carbon. These stars exhibit diverse abundance patterns, particularly for heavy elements, based on which they are classified into different groups. The diversity of abundance patterns points at different formation scenarios. Hence, accurate classification of CEMP stars and knowledge of their distribution is essential to understand the role and contribution of each group. While CEMP-s and CEMP-r/s stars can be used to get insight into binary interactions at very low metallicity, CEMP-no stars can be used to probe the properties of the first stars and early nucleosynthesis. To exploit the full potential of CEMP stars for Galactic archaeology a homogeneous analysis of each class is extremely important. Our efforts towards, and contributions to providing an improved classification scheme for accurate classification of CEMP-s and CEMP-r/s stars and in characterizing the companion asymptotic giant branch (AGB) stars of CH, CEMP-no, CEMP-s and CEMP-r/s binary systems are discussed. Some recent results obtained based on low- and high-resolution spectroscopic analysis of a large number of potential CH and CEMP star candidates are highlighted.", "keyphrases": ["metal-poor stars", "carbon stars", "nucleosynthesis", "abundances"]}
{"id": "bilenko2023meridional", "title": "Meridional Circulations of the Solar Magnetic Fields of Different Strength", "abstract": "The meridional circulation of the solar magnetic fields in Solar Cycles 21-24 was considered. Data from both ground-based and space observatories were used. Three types of time-latitude distributions of photospheric magnetic fields and their meridional circulations were identified depending on the magnetic field intensity. (i) low-strength magnetic fields. They were distributed evenly across latitude and weakly depended on the magnetic fields of active regions and their cycle variation; (ii) medium-strength magnetic fields. For these fields a wave-like, pole-to-pole, antiphase meridional circulation with a period of approximately 22 years was revealed. The velocities of meridional flows were slower at the minima of solar activity, when they were at high latitudes in the opposite hemispheres, and maximal at the solar maxima, when the positive- and negative-polarity waves crossed the equator. The meridional circulation of these fields reflects the solar global magnetic field dynamics and determines the solar polar field reversal; (iii) high-strength (active region) magnetic fields. They were distributed symmetrically in the Northern and Southern hemispheres. Magnetic fields of both leading and following sunspot polarity migrated from high to low latitudes. The meridional-flow velocities of high-strength magnetic fields were higher at the rising and maxima phases than at the minima. Some of the high-latitude active region magnetic fields were captured by the second type meridional circulation flows and transported along with them to the appropriate pole. But the magnetic fields of active regions are not the main ones in the solar polar field reversal. The results indicate that high-strength magnetic fields were not the main source of weak ones.", "keyphrases": ["magnetic fields", "latitudinal drifts", "meridional flow", "solar cycle"]}
{"id": "merle2023dancing", "title": "Dancing with the stars: a review on stellar multiplicity", "abstract": "Stars like company. They are mostly formed in clusters and their lives are often altered by the presence of one or more companions. Interaction processes between components may lead to complex outcomes like Algols, blue stragglers, chemically altered stars, type Ia supernovae, as well as progenitors of gravitational wave sources, to cite a few. Observational astronomy has entered the era of big data, and thanks to large surveys like spatial missions Kepler, TESS, Gaia, and ground-based spectroscopic surveys like RAVE, Gaia-ESO, APOGEE, LAMOST, GALAH (to name a few) the field is going through a true revolution, as illustrated by the recent detection of stellar black holes and neutron stars as companions of massive but also low-mass stars. In this review, I will present why it is important to care about stellar multiples, what are the main large surveys in which many binaries are harvested, and finally present some features related to the largest catalogue of astrometric, spectroscopic and eclipsing binaries provided by the Non-Single Star catalogue of Gaia, which is, to date, the largest homogeneous catalogue of stellar binaries.", "keyphrases": ["binary stars", "stellar multiplicity", "spectroscopic binaries", "eclipsing binaries", "astrometric binaries"]}
{"id": "ashley2023metallicities", "title": "The Metallicities of Five Small High-Velocity Clouds", "abstract": "High-velocity clouds (HVCs) are multi-phase gas structures whose velocities (|v_LSR|>100 km/s) are too high to be explained by Galactic disk rotation. While large HVCs are well characterized, compact and small HVCs (with HI angular sizes of a few degrees) are poorly understood. Possible origins for such small clouds include Milky Way halo gas or fragments of the Magellanic System, but neither their origin nor their connection to the Milky Way halo has been confirmed. We use new Hubble Space Telescope/Cosmic Origins Spectrograph UV spectra and Green Bank Telescope HI spectra to measure the metallicities of five small HVCs in the southern Galactic sky projected near the Magellanic System. We build a set of distance-dependent Cloudy photoionization models for each cloud and calculate their ionization-corrected metallicities. All five small HVCs have oxygen metallicities <0.17 Z_sun, indicating they do not originate in the disk of the Milky Way. Two of the five have metallicities of 0.16-0.17 Z_sun, similar to the Magellanic Stream, suggesting these clouds are fragments of the Magellanic System. The remaining three clouds have much lower metallicities of 0.02-0.04 Z_sun. While the origin of these low-metallicity clouds is unclear, they could be gaseous mini-halos or gas stripped from dwarf galaxies by ram pressure or tidal interactions. These results suggest that small HVCs do not all reside in the inner Milky Way halo or the Magellanic System, but instead can trace more distant structures.", "keyphrases": ["milky way galaxy", "galactic halo", "ultraviolet astronomy", "high-velocity clouds", "chemical abundances"]}
{"id": "wevers2023delayed", "title": "Delayed X-ray brightening accompanied by variable ionized absorption following a tidal disruption event", "abstract": "Supermassive black holes can experience super-Eddington peak mass fallback rates following the tidal disruption of a star. The theoretical expectation is that part of the infalling material is expelled by means of an accretion disk wind, whose observational signature includes blueshifted absorption lines of highly ionized species in X-ray spectra. To date, however, only one such ultra-fast outflow (UFO) has been reported in the tidal disruption event (TDE) ASASSN-14li. Here we report on the discovery of transient absorption-like signatures in X-ray spectra of the TDE AT2020ksf/Gaia20cjk (at a redshift of z=0.092), following an X-ray brightening \u223c230 days after UV/optical peak. We find that while no statistically significant absorption features are present initially, they appear on a timescale of several days, and remain detected up to 770 days after peak. Simple thermal continuum models, combined with a power-law or neutral absorber, do not describe these features well. Adding a partial covering, low velocity ionized absorber improves the fit at early times, but fails at late times. A high velocity (vw \u223c 42000 km s\u22121, or -0.15c), ionized absorber (ultra-fast outflow) provides a good fit to all data. The few day timescale of variability is consistent with expectations for a clumpy wind. We discuss several scenarios that could explain the X-ray delay, as well as the potential for larger scale wind feedback. The serendipitous nature of the discovery could suggest a high incidence of UFOs in TDEs, alleviating some of the tension with theoretical expectations.", "keyphrases": ["tidal disruption events", "black holes", "accretion disks"]}
{"id": "murguiaberthier2023feast", "title": "From Feast to Famine: A Systematic Study of Accretion onto Oblique Pulsars with 3D GRMHD Simulations", "abstract": "Disk-fed accretion onto neutron stars can power a wide range of astrophysical sources ranging from X-ray binaries, to accretion powered millisecond pulsars, ultra-luminous X-ray sources, and gamma-ray bursts. A crucial parameter controlling the gas-magnetosphere interaction is the strength of the stellar dipole. In addition, coherent X-ray pulsations in many neutron star systems indicate that the star's dipole moment is oblique relative to its rotation axis. Therefore, it is critical to systematically explore the 2D parameter space of the star's magnetic field strength and obliquity, which is what this work does, for the first time, in the framework of 3D general-relativistic magnetohydrodynamics. If the accretion disk carries its own vertical magnetic field, this introduces an additional factor: the relative polarity of the disk and stellar magnetic fields. We find that depending on the strength of the stellar dipole and the star-disk relative polarity, the neutron star's jet power can either increase or decrease with increasing obliquity. For weak dipole strength (equivalently, high accretion rate), the parallel polarity results in a positive correlation between jet power and obliquity, whereas the anti-parallel orientation displays the opposite trend. For stronger dipoles, the relative polarity effect disappears, and jet power always decreases with increasing obliquity. The influence of the relative polarity gradually disappears as obliquity increases. Highly oblique pulsars tend to have an increased magnetospheric radius, a lower mass accretion rate, and enter the propeller regime at lower magnetic moments than aligned stars.", "keyphrases": ["accretion", "pulsars", "neutron stars", "magnetohydrodynamics", "relativistic jets", "general relativity"]}
{"id": "nishiyama2023origin", "title": "Origin of an Orbiting Star Around the Galactic Supermassive Black Hole", "abstract": "The tremendous tidal force that is linked to the supermassive black hole (SMBH) at the center of our galaxy is expected to strongly subdue star formation in its vicinity. Stars within 1\" from the SMBH thus likely formed further from the SMBH and migrated to their current positions. In this study, spectroscopic observations of the star S0-6/S10, one of the closest (projected distance from the SMBH of about 0.3\") late-type stars were conducted. Using metal absorption lines in the spectra of S0-6, the radial velocity of S0-6 from 2014 to 2021 was measured, and a marginal acceleration was detected, which indicated that S0-6 is close to the SMBH. The S0-6 spectra were employed to determine its stellar parameters including temperature, chemical abundances ([M/H], [Fe/H], [alpha/Fe], [Ca/Fe], [Mg/Fe], [Ti/Fe]), and age. As suggested by the results of this study, S0-6 is very old (> \u00a010 Gyr) and has an origin different from that of stars born in the central pc region.", "keyphrases": ["astrophysics", "infrared astronomy", "black hole", "spectroscopy"]}
{"id": "li2023simultaneous", "title": "Simultaneous detection of flare-associated kink oscillations and extreme-ultraviolet waves", "abstract": "Kink oscillations, which are frequently observed in coronal loops and prominences, are often accompanied by extreme-ultraviolet (EUV) waves. However, much more needs to be explored regarding the causal relationships between kink oscillations and EUV waves. In this article, we report the simultaneous detection of kink oscillations and EUV waves that are both associated with an X2.1 flare on 2023 March 03 (SOL2023-03-03T17:39). The kink oscillations, which are almost perpendicular to the axes of loop-like structures, are observed in three coronal loops and one prominence. One short loop shows in-phase oscillation within the same period of 5.2 minutes at three positions. This oscillation could be triggered by the pushing of an expanding loop and interpreted as the standing kink wave. Time lags are found between the kink oscillations of the short loop and two long loops, suggesting that the kink wave travels in different loops. The kink oscillations of one long loop and the prominence are possibly driven by the disturbance of the CME, and that of another long loop might be attributed to the interaction of the EUV wave. The onset time of the kink oscillation of the short loop is nearly same as the beginning of an EUV wave. This fact demonstrates that they are almost simultaneous. The EUV wave is most likely excited by the expanding loop structure and shows two components. The leading component is a fast coronal wave, and the trailing one could be due to the stretching magnetic field lines.", "keyphrases": ["coronal loops", "solar flares", "solar prominence", "solar oscillations", "euv wave", "magnetohydrodynamic (mhd)"]}
{"id": "zadorozhna2023study", "title": "The study of x-ray spectrum of the Coma cluster", "abstract": "The X-ray spectrum of the Coma galaxy cluster was studied using the data from the XMM-Newton observatory. We combined 7 observations performed with the MOS camera of XMM-Newton in the 40'x 40' region centered at the Coma cluster. The analyzed observations were performed in 2000-2005 and have a total duration of 196 ksec.We focus on the analysis of the MOS camera spectra due to their lower affection by strong instrumental line-like background. The obtained spectrum was fitted with a model including contributions from the Solar system/Milky Way hot plasma and a power law X-ray background. The contribution of the instrumental background was modeled as a power law (not convolved with the effective area) and a number of Gaussian lines. The contribution from the Coma cluster was modeled with a single-temperature hot plasma emission. In addition, we searched for possible non-thermal radiation present in the vicinity of the center of the Coma cluster, originating e.g. from synchrotron emission of relativistic electrons on a turbulent magnetic field. We compared the results with previous works by other authors and spectra obtained from other instruments that operate in the similar energy range of 1-10 keV. Careful and detailed spectrum analysis shall be a necessary contribution to our future work - searching for axion-like particles' manifestations in the Coma cluster.", "keyphrases": ["clusters of galaxies", "intergalactic plasma", "non-thermal radiation", "xmm-newton", "x-ray radiation"]}
{"id": "borghese2023isolated", "title": "Isolated Neutron Stars", "abstract": "Non-accreting neutron stars display diverse characteristics, leading us to classify them into several groups. This chapter is an observational driven review in which we survey the properties of the different classes of isolated neutron stars: from the 'normal' rotation-powered pulsars, to magnetars, the most magnetic neutron stars in the Universe we know of; from central compact objects (sometimes called also anti-magnetars) in supernova remnants, to the X-ray dim isolated neutron stars. We also highlight a few sources that have exhibited features straddling those of different sub-groups, blurring the apparent diversity of the neutron star zoo and pointing to a gran unification.", "keyphrases": ["isolated neutron stars", "rotation-powered pulsars", "magnetars", "x-ray dim isolated neutron stars", "central compact objects"]}
{"id": "li2023research", "title": "Research on the X-Ray Polarization Deconstruction Method Based on Hexagonal Convolutional Neural Network", "abstract": "Track reconstruction algorithms are critical for polarization measurements. In addition to traditional moment-based track reconstruction approaches, convolutional neural networks (CNN) are a promising alternative. However, hexagonal grid track images in gas pixel detectors (GPD) for better anisotropy do not match the classical rectangle-based CNN, and converting the track images from hexagonal to square results in loss of information. We developed a new hexagonal CNN algorithm for track reconstruction and polarization estimation in X-ray polarimeters, which was used to extract emission angles and absorption points from photoelectron track images and predict the uncertainty of the predicted emission angles. The simulated data of PolarLight test were used to train and test the hexagonal CNN models. For individual energies, the hexagonal CNN algorithm produced 15-30", "keyphrases": ["x-ray polarization", "track reconstruction", "deep learning", "hexagonal conventional neural network"]}
{"id": "young2023retrievals", "title": "Retrievals Applied To A Decision Tree Framework Can Characterize Earth-like Exoplanet Analogs", "abstract": "Exoplanet characterization missions planned for the future will soon enable searches for life beyond our solar system. Critical to the search will be the development of life detection strategies that can search for biosignatures while maintaining observational efficiency. In this work, we adopted a newly developed biosignature decision tree strategy for remote characterization of Earth-like exoplanets. The decision tree offers a step-by-step roadmap for detecting exoplanet biosignatures and excluding false positives based on Earth's biosphere and its evolution over time. We followed the pathways for characterizing a modern Earth-like planet and an Archean Earth-like planet and evaluated the observational trades associated with coronagraph bandpass combinations of designs consistent with The Habitable Worlds Observatory (HWO) precursor studies. With retrieval analyses of each bandpass (or combination), we demonstrate the utility of the decision tree and evaluated the uncertainty on a suite of biosignature chemical species and habitability indicators (i.e., the gas abundances of H2O, O2, O3, CH4, and CO2). Notably for modern Earth, less than an order of magnitude spread in the 1-\u03c3 uncertainties were achieved for the abundances of H2O and O2, planetary surface pressure, and atmospheric temperature with three strategically placed bandpasses (two in the visible and one in the near-infrared). For the Archean, CH4 and H2O were detectable in the visible with a single bandpass.", "keyphrases": ["exoplanets", "biosignatures", "direct imaging", "spectral retrievals"]}
{"id": "williams2023galaxies", "title": "The galaxies missed by Hubble and ALMA: the contribution of extremely red galaxies to the cosmic census at 3<z<8", "abstract": "Using deep JWST imaging from JADES, JEMS and SMILES, we characterize optically-faint and extremely red galaxies at z>3 that were previously missing from galaxy census estimates. The data indicate the existence of abundant, dusty and post-starburst-like galaxies down to 108M\u2299, below the sensitivity limit of Spitzer and ALMA. Modeling the NIRCam and HST photometry of these red sources can result in extreme, high values for both stellar mass and star formation rate (SFR); however, including 7 MIRI filters out to 21\u03bcm results in decreased mass (median 0.6 dex for log10M\u2217/M\u2299>10), and SFR (median 10\u00d7 for SFR>100 M\u2299/yr). At z>6, our sample includes a high fraction of little red dots (LRDs; NIRCam-selected dust-reddened AGN candidates). We significantly measure older stellar populations in the LRDs out to rest-frame 3\u03bcm (the stellar bump) and rule out a dominant contribution from hot dust emission, a signature of AGN contamination to stellar population measurements. This allows us to measure their contribution to the cosmic census at z>3, below the typical detection limits of ALMA (LIR<1012L\u2299). We find that these sources, which are overwhelmingly missed by HST and ALMA, could effectively double the obscured fraction of the star formation rate density at 4<z<6 compared to some estimates, showing that prior to JWST, the obscured contribution from fainter sources could be underestimated. Finally, we identify five sources with evidence for Balmer breaks and high stellar masses at 5.5<z<7.7. While spectroscopy is required to determine their nature, we discuss possible measurement systematics to explore with future data.", "keyphrases": ["high-redshift galaxies", "active galaxies", "agn host galaxies"]}
{"id": "cumner2023effects", "title": "The effects of the antenna power pattern uncertainty within a global 21 cm experiment", "abstract": "Experimental 21 cm cosmology aims to detect the formation of the first stars during the cosmic dawn and the subsequent epoch of reionization by utilizing the 21 cm hydrogen line transition. While several experiments have published results that begin to constrain the shape of this signal, a definitive detection has yet to be achieved. In this paper, we investigate the influence of uncertain antenna-sky interactions on the possibility of detecting the signal. This paper aims to define the level of accuracy to which a simulated antenna beam pattern is required to agree with the actual observing beam pattern of the antenna to allow for a confident detection of the global 21 cm signal. By utilising singular value decomposition, we construct a set of antenna power patterns that incorporate minor, physically motivated variations. We take the absolute mean averaged difference between the original beam and the perturbed beam averaged over frequency (\u0394D) to quantifying this difference, identifying the correlation between \u0394D and antenna temperature. To analyse the impact of \u0394D on making a confident detection, we utilize the REACH Bayesian analysis pipeline and compare the Bayesian evidence log\ue246 and root-mean-square error for antenna beams of different \u0394D values. Our calculations suggest that achieving an agreement between the original and perturbed antenna power pattern with \u0394D better than -35 dB is necessary for confident detection of the global 21 cm signal. Furthermore, we discuss potential methods to achieve the required high level of accuracy within a global 21\u00a0cm experiment.", "keyphrases": ["21 cm cosmology", "systematic uncertainties", "computational modelling"]}
{"id": "vanalfen2023empirical", "title": "An Empirical Model For Intrinsic Alignments: Insights From Cosmological Simulations", "abstract": "We extend current models of the halo occupation distribution (HOD) to include a flexible, empirical framework for the forward modeling of the intrinsic alignment (IA) of galaxies. A primary goal of this work is to produce mock galaxy catalogs for the purpose of validating existing models and methods for the mitigation of IA in weak lensing measurements. This technique can also be used to produce new, simulation-based predictions for IA and galaxy clustering. Our model is probabilistically formulated, and rests upon the assumption that the orientations of galaxies exhibit a correlation with their host dark matter (sub)halo orientation or with their position within the halo. We examine the necessary components and phenomenology of such a model by considering the alignments between (sub)halos in a cosmological dark matter only simulation. We then validate this model for a realistic galaxy population in a set of simulations in the Illustris-TNG suite. We create an HOD mock with Illustris-like correlations using our method, constraining the associated IA model parameters, with the \u03c72dof between our model's correlations and those of Illustris matching as closely as 1.4 and 1.1 for orientation\u2013position and orientation\u2013orientation correlation functions, respectively. By modeling the misalignment between galaxies and their host halo, we show that the 3-dimensional two-point position and orientation correlation functions of simulated (sub)halos and galaxies can be accurately reproduced from quasi-linear scales down to 0.1 h\u22121Mpc. We also find evidence for environmental influence on IA within a halo. Our publicly-available software provides a key component enabling efficient determination of Bayesian posteriors on IA model parameters using observational measurements of galaxy-orientation correlation functions in the highly nonlinear regime.", "keyphrases": ["cosmology", "weak gravitational lensing", "intrinsic alignments"]}
{"id": "du2023starforming", "title": "Star-forming Main Sequence of Giant Low Surface Brightness Galaxies", "abstract": "Giant Low Surface Brightness Galaxies (GLSBGs) are fundamentally distinct from normal galaxies (LSBGs) in star formation and evolution. In this work, we collected 27 local GLSBGs. They have high stellar masses (M*>10^10 Msolar) and low SFRs. With the specific SFRs lower than the characteristic value of the local star-forming (SF) galaxies of M*=10^10 Msolar(sSFR < 0.1 Gyr^-1), GLSBGs deviate from the SF main sequence (MS) defined for local SFGs respectively by E07 and S16 at the high M* regime. They are HI-rich systems with HI gas mass fractions (fHI) higher than the S16 MS galaxies, but have little molecular gas (H2), implying a low efficiency of HI-to-H2 transition due to the low HI surface densities that are far lower than the minimum of 6 - 8 Msolar pc^-2 required for shielding the formed H2 from photodissociation. For GLSBGs, the inner, bulge-dominated part with lower SFRs and higher M* is the main force pulling the entire GLSBG off from the MS, while the outer, disk-dominated part with relatively higher SFRs and lower M* reduces the deviations from the MS. For some cases, the outer, disk-dominated parts even tend to follow the MS. In the aspect of NUV - r versus g - r colors, the outer, disk-dominated parts are blue and behave similarly to the normal star-forming galaxies while the inner, bulge-dominated parts are in statistics red, indicating an inside-out star formation mechanism for the GLSBGs. They show few signs of external interactions in morphology, excluding the recent major merger scenario.", "keyphrases": ["low surface brightness galaxies", "star formation rate", "stellar mass", "star formation mechanism", "hi", "h2", "gas surface density"]}
{"id": "makishima2023evidence", "title": "Further Evidence for the \u00a0 9 s Pulsation in LS 5039 from NuSTAR and ASCA", "abstract": "The present study aims to reinforce the evidence for the \u00a09 s pulsation in the gamma-ray binary LS 5039, derived with a Suzaku observation in 2007 and that with NuSTAR in 2016 (Yoneda et al 2000). Through a reanalysis of the NuSTAR data incorporating the orbital Doppler correction, the 9.0538 s pulsation was confirmed successfully even in the 3\u201310 keV range, where it was undetectable previously. This was attained by perceiving an energy-dependent drift in the pulse phase below 10 keV, and correcting the pulse timing of individual photons for that effect. Similarly, an archival 0.7\u201312 keV data set of LS 5039, taken with the ASCA GIS in 1999 October, was analyzed. The data showed possible periodicity at about 8.882 s, but again the energy-dependent phase drift was noticed below 10 keV. By correcting for this effect, and for the orbital Doppler delays in the LS 5039 system, the 2.8\u201312 keV periodicity became statistically significant at 8.891+- 0.001 s. The periods measured with ASCA, Suzaku, and NuSTAR approximately follow an average period derivative of dP/dt = 3.0 e-10 s/s. These results provide further evidence for the pulsation in this object, and strengthen the scenario by (Yoneda et al 2000), that the compact object in LS 5039 is a strongly magnetized neutron star.", "keyphrases": ["astrophysical magnetism", "gamma-ray sources", "magnetars", "neutron stars", "pulsars"]}
{"id": "groh2023crosstalk", "title": "Crosstalk effects in microwave SQUID multiplexed TES bolometer readout", "abstract": "Transition-edge sensor (TES) bolometers are broadly used for background-limited astrophysical measurements from the far-infrared to mm-waves. Many planned future instruments require increasingly large detector arrays, but their scalability is limited by their cryogenic readout electronics. Microwave SQUID multiplexing offers a highly capable scaling solution through the use of inherently broadband circuitry, enabling readout of hundreds to thousands of channels per microwave line. As with any multiplexing technique, the channelization mechanism gives rise to electrical crosstalk which must be understood and controlled so as to not degrade the instrument sensitivity. Here, we explore implications relevant for TES bolometer array applications, focusing in particular on upcoming mm-wave observatories such as the Simons Observatory and AliCPT. We model the relative contributions of the various underlying crosstalk mechanisms, evaluate the difference between fixed-tone and tone-tracking readout systems, and discuss ways in which crosstalk nonlinearity will complicate on-sky measurements.", "keyphrases": ["crosstalk", "multiplexing", "microwave squid", "tes"]}
{"id": "prasad2023case", "title": "The Case for Hot-Mode Accretion in Abell 2029", "abstract": "Radiative cooling and AGN heating are thought to form a feedback loop that regulates the evolution of low redshift cool-core galaxy clusters. Numerical simulations suggest that formation of multiphase gas in the cluster core imposes a floor on the ratio of cooling time (tcool) to free-fall time (tff) at min(tcool/tff)\u224810. Observations of galaxy clusters show evidence for such a floor, and usually the cluster cores with min(tcool/tff)\u227230 contain abundant multiphase gas. However, there are important outliers. One of them is Abell 2029, a massive galaxy cluster (M200\u22731015 M\u2299) with min(tcool/tff)\u223c20, but little apparent multiphase gas. In this paper, we present high resolution 3D hydrodynamic AMR simulations of a cluster similar to A2029 and study how it evolves over a period of 1-2 Gyr. Those simulations suggest that Abell 2029 self-regulates without producing multiphase gas because the mass of its central black hole (\u223c5\u00d71010M\u2299) is great enough for Bondi accretion of hot ambient gas to produce enough feedback energy to compensate for radiative cooling.", "keyphrases": ["galaxy clusters", "cooling flow", "black hole", "agn feedback", "intracluster medium"]}
{"id": "monsch2023linking", "title": "Linking circumstellar disk lifetimes to the rotational evolution of low-mass stars", "abstract": "The high-energy radiation emitted by young stars can have a strong influence on their rotational evolution at later stages. This is because internal photoevaporation is one of the major drivers of the dispersal of circumstellar disks, which surround all newly born low-mass stars during the first few million years of their evolution. Employing an internal EUV/X-ray photoevaporation model, we have derived a simple recipe for calculating realistic inner disk lifetimes of protoplanetary disks. This prescription was implemented into a magnetic morphology-driven rotational evolution model and is used to investigate the impact of disk-locking on the spin evolution of low-mass stars. We find that the length of the disk-locking phase has a profound impact on the subsequent rotational evolution of a young star, and the implementation of realistic disk lifetimes leads to an improved agreement of model outcomes with observed rotation period distributions for open clusters of various ages. However, for both young star-forming regions tested in our model, the strong bimodality in rotation periods that is observed in hPer could not be recovered. hPer is only successfully recovered, if the model is started from a double-peaked distribution with an initial disk fraction of 65", "keyphrases": ["stellar rotation", "protoplanetary disks", "star-disk interactions", "low-mass stars"]}
{"id": "anche2023simulation", "title": "Simulation of high-contrast polarimetric observations of debris disks with the Roman Coronagraph Instrument", "abstract": "The Nancy Grace Roman Space Telescope Coronagraph Instrument will enable the polarimetric imaging of debris disks and inner dust belts in the optical and near-infrared wavelengths, in addition to the high-contrast polarimetric imaging and spectroscopy of exoplanets. The Coronagraph uses two Wollaston prisms to produce four orthogonally polarized images and is expected to measure the polarization fraction with measurement errors < 3", "keyphrases": ["debris disks", "high contrast imaging", "polarization observations", "coronagraphs", "exozodis"]}
{"id": "malherbe2023note", "title": "Note concerning a high spectral resolution slicer for imaging spectro-polarimetry with the new generation Multichannel Subtractive Double Pass (MSDP) onboard the future EST telescope", "abstract": "Imaging spectroscopy is intended to be coupled with adaptive optics (AO) on large telescopes, such as EST, in order to produce high spatial and temporal resolution measurements of velocities and magnetic fields upon a 2D FOV. We propose a high spectral resolution slicer (30 m\u00c5 typical) for the Multichannel Subtractive Double Pass (MSDP) of the future European Solar Telescope (EST), using a new generation slicer for thin photospheric lines such as FeI (56 channels, 0.13 mm step) which will benefit of AO and existing polarimeters. The aim is to reconstitute cubes of instantaneous data (X, Y, lambda) at high cadence, allowing the study of the photospheric dynamics and magnetic fields.", "keyphrases": ["imaging spectroscopy", "polarimetry", "msdp", "solar physics", "photosphere", "chromosphere"]}
{"id": "pfeifle2023high", "title": "The High Energy X-ray Probe (HEX-P): The Future of Hard X-ray Dual AGN Science", "abstract": "A fundamental goal of modern-day astrophysics is to understand the connection between supermassive black hole (SMBH) growth and galaxy evolution. Merging galaxies offer one of the most dramatic channels for galaxy evolution known, capable of driving inflows of gas into galactic nuclei, potentially fueling both star formation and central SMBH activity. Dual active galactic nuclei (dual AGNs) in late-stage mergers with nuclear pair separations <10 kpc are thus ideal candidates to study SMBH growth along the merger sequence since they coincide with the most transformative period for galaxies. However, dual AGNs can be extremely difficult to confirm and study. Hard X-ray (>10 keV) studies offer a relatively contamination-free tool for probing the dense obscuring environments predicted to surround the majority of dual AGN in late-stage mergers. To date, only a handful of the brightest and closest systems have been studied at these energies due to the demanding instrumental requirements involved. We demonstrate the unique capabilities of HEX-P to spatially resolve the soft and - for the first time - hard X-ray counterparts of closely-separated (\u223c2\u2033\u22125\u2033) dual AGNs in the local Universe. By incorporating state-of-the-art physical torus models, we reproduce realistic broadband X-ray spectra expected for deeply embedded accreting SMBHs. Hard X-ray spatially resolved observations of dual AGNs - accessible only to HEX-P - will hence transform our understanding of dual AGN in the nearby Universe.", "keyphrases": ["dual agn", "galaxy merger", "x-ray astronomy", "active galactic nucleus", "galaxy interaction"]}
{"id": "garnavich2023rapid", "title": "Rapid Evolution of the White Dwarf Pulsar AR Scorpii", "abstract": "Analysis of AR Sco optical light curves spanning nine years show a secular change in the relative amplitudes of the beat pulse pairs generated by the two magnetic poles of its rotating white dwarf. Recent photometry now shows that the primary and secondary beat pulses have similar amplitudes, while in 2015 the primary pulse was approximately twice that of the secondary peak. The equalization in the beat pulse amplitudes is also seen in the linearly polarized flux. This rapid evolution is consistent with precession of the white dwarf spin axis. The observations imply that the pulse amplitudes cycle over a period of \u227340 yrs, but that the upper limit is currently poorly constrained. If precession is the mechanism driving the evolution, then over the next 10 years the ratio of the beat pulse amplitudes will reach a maximum followed by a return to asymmetric beat pulses.", "keyphrases": ["cataclysmic variable stars", "intermediate polars", "white dwarf stars", "magnetic poles", "rotation powered pulsars"]}
{"id": "reynolds2023high", "title": "The High Energy X-ray Probe (HEX-P): Supernova remnants, pulsar wind nebulae, and nuclear astrophysics", "abstract": "HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging (<10\" full width at half maximum) and broad spectral coverage (0.2\u201380 keV) with an effective area far superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. HEX-P is ideally suited to address important problems in the physics and astrophysics of supernova remnants (SNRs) and pulsar-wind nebulae (PWNe). For shell SNRs, HEX-P can greatly improve our understanding via more accurate spectral characterization and localization of non-thermal X-ray emission from both non-thermal-dominated SNRs and those containing both thermal and non-thermal components, and can discover previously unknown non-thermal components in SNRs. Multi-epoch HEX-P observations of several young SNRs (e.g., Cas A and Tycho) are expected to detect year-scale variabilities of X-ray filaments and knots, thus enabling us to determine fundamental parameters related to diffusive shock acceleration, such as local magnetic field strengths and maximum electron energies. For PWNe, HEX-P will provide spatially-resolved, broadband X-ray spectral data separately from their pulsar emission, allowing us to study how particle acceleration, cooling, and propagation operate in different evolution stages of PWNe. HEX-P is also poised to make unique and significant contributions to nuclear astrophysics of Galactic radioactive sources by improving detections of, or limits on, 44Ti in the youngest SNRs and by potentially discovering rare nuclear lines as evidence of double neutron star mergers. Throughout the paper, we present simulations of each class of objects, demonstrating the power of both the imaging and spectral capabilities of HEX-P to advance our knowledge of SNRs, PWNe, and nuclear astrophysics.", "keyphrases": ["supernova remnants", "pulsar wind nebulae", "nuclear astrophysics", "x-ray astrophysics", "future missions"]}
{"id": "boorman2023high", "title": "The High Energy X-ray Probe (HEX-P): The Circum-nuclear Environment of Growing Supermassive Black Holes", "abstract": "Ever since the discovery of the first Active Galactic Nuclei (AGN), substantial observational and theoretical effort has been invested into understanding how massive black holes have evolved across cosmic time. Circum-nuclear obscuration is now established as a crucial component, with almost every AGN observed known to display signatures of some level of obscuration in their X-ray spectra. But despite more than six decades of effort, substantial open questions remain: How does the accretion power impact the structure of the circum-nuclear obscurer? What are the dynamical properties of the obscurer? Can dense circum-nuclear obscuration exist around intrinsically weak AGN? How many intermediate mass black holes occupy the centers of dwarf galaxies? In this paper, we showcase a number of next-generation prospects attainable with the High Energy X-ray Probe (this https URL) to contribute towards solving these questions in the 2030s. The uniquely broad (0.2\u201380 keV) and strictly simultaneous X-ray passband of HEX-P makes it ideally suited for studying the temporal co-evolution between the central engine and circum-nuclear obscurer. Improved sensitivities and reduced background will enable the development of spectroscopic models complemented by current and future multi-wavelength observations. We show that the angular resolution of HEX-P both below and above 10 keV will enable the discovery and confirmation of accreting massive black holes at both low accretion power and low black hole masses even when concealed by thick obscuration. In combination with other next-generation observations of the dusty hearts of nearby galaxies, HEX-P will hence be pivotal in paving the way towards a complete picture of black hole growth and galaxy co-evolution.", "keyphrases": ["x-ray", "agn", "obscuration", "black hole", "galaxies", "compton-thick", "high energy", "spectral modelling"]}
{"id": "kane2023modeling", "title": "Modeling of cosmic rays and near-IR photons in aluminum KIDs", "abstract": "The PRobe far-Infrared Mission for Astrophysics (PRIMA) is working to develop kinetic inductance detectors (KIDs) that can meet the sensitivity targets of a far-infrared spectrometer on a cryogenically cooled space telescope. An important ingredient for achieving high sensitivity is increasing the fractional-frequency responsivity. Here we present a study of the responsivity of aluminum KIDs fabricated at the Jet Propulsion Laboratory. Specifically, we model the KID's temporal response to pair-breaking excitations in the framework of the Mattis-Bardeen theory, incorporating quasiparticle recombination dynamics and the pair-breaking efficiency. Using a near-IR laser, we measure time-resolved photon pulses and fit them to our model, extracting the time-resolved quasiparticle density and the quasiparticle recombination lifetime. Comparing the fit to the known energy of the laser provides a measurement of the pair-breaking efficiency. In addition to photon-sourced excitations, it is important to understand the KID's response to phonon-sourced excitations from cosmic rays. We measure the rate of secondary cosmic rays detected by our devices, and predict the dead time due to cosmic rays for an array in L2 orbit. This work provides confidence in KIDs' robustness to cosmic ray events in the space environment.", "keyphrases": ["far-infrared", "kinetic inductance detectors", "cosmic rays", "quasiparticle lifetime", "pair-breaking efficiency"]}
{"id": "mori2023high", "title": "The High Energy X-ray Probe (HEX-P): Galactic PeVatrons, star clusters, superbubbles, microquasar jets, and gamma-ray binaries", "abstract": "HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging (<10\" FWHM) and broad spectral coverage (0.2-80 keV) with an effective area far superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. With the recent discoveries of over 40 ultra-high-energy gamma-ray sources (detected above 100 TeV) and neutrino emission in the Galactic Plane, we have entered a new era of multi-messenger astrophysics facing the exciting reality of Galactic PeVatrons. In the next decade, as more Galactic PeVatrons and TeV gamma-ray sources are expected to be discovered, the identification of their acceleration and emission mechanisms will be the most pressing issue in both particle and high-energy astrophysics. In this paper, along with its companion papers (Reynolds et al. 2023, Mori et al. 2023), we will present that HEX-P is uniquely suited to address important problems in various cosmic-ray accelerators, including Galactic PeVatrons, through investigating synchrotron X-ray emission of TeV-PeV electrons produced by both leptonic and hadronic processes.", "keyphrases": ["particle accelerators", "galactic pevatrons", "star clusters", "superbubbles", "microquasars", "gamma-ray binaries", "x-ray telescopes", "multimessenger astronomy"]}
{"id": "herbst2023impact", "title": "Impact of Cosmic Rays on Atmospheric Ion Chemistry and Spectral Transmission Features of TRAPPIST-1e", "abstract": "Ongoing observing projects like the James Webb Space Telescope (JWST) and future missions offer the chance to characterize Earth-like exoplanetary atmospheres. Thereby, M-dwarfs are preferred targets for transit observations, for example, due to their favorable planet-star contrast ratio. However, the radiation and particle environment of these cool stars could be far more extreme than what we know from the Sun. Thus, knowing the stellar radiation and particle environment and its possible influence on detectable biosignatures - particularly signs of life like ozone and methane - is crucial to understanding upcoming transit spectra. In this study, with the help of our unique model suite INCREASE, we investigate the impact of a strong stellar energetic particle event on the atmospheric ionization, neutral and ion chemistry, and atmospheric biosignatures of TRAPPIST-1e. Therefore, transit spectra for six scenarios are simulated. We find that a Carrington-like event drastically increases atmospheric ionization and induces substantial changes in ion chemistry and spectral transmission features: all scenarios show high event-induced amounts of nitrogen dioxide (i.e., at 6.2 \u03bcm), a reduction of the atmospheric transit depth in all water bands (i.e., at 5.5 \u2013 7.0 \u03bcm), a decrease of the methane bands (i.e., at 3.0 \u2013 3.5 \u03bcm), and depletion of ozone (i.e., at \u223c 9.6 \u03bcm). Therefore, it is essential to include high-energy particle effects to correctly assign biosignature signals from, e.g., ozone and methane. We further show that the nitric acid feature at 11.0 - 12.0 \u03bcm, discussed as a proxy for stellar particle contamination, is absent in wet-dead atmospheres.", "keyphrases": ["exoplanets", "cosmic rays", "exoplanet atmospheres", "photoionization", "exoplanet atmospheric composition", "biosignatures"]}
{"id": "choudhuri2023nearsurface", "title": "The Near-surface Shear Layer (NSSL) of the Sun: A Theoretical Model", "abstract": "We present a theoretical model of the near-surface shear layer (NSSL) of the Sun. Convection cells deeper down are affected by the Sun's rotation, but this is not the case in a layer just below the solar surface due to the smallness of the convection cells there. Based on this idea, we show that the thermal wind balance equation (the basic equation in the theory of the meridional circulation which holds inside the convection zone) can be solved to obtain the structure of the NSSL, matching observational data remarkably well.", "keyphrases": ["differential rotation", "meridional circulation", "convection", "near-surface shear layer"]}
{"id": "neomenko2023constraints", "title": "Constraints on the interaction of quintessence dark energy with dark matter and the evolution of its equation of state parameter", "abstract": "The cosmological model with an interaction between dynamical quintessence dark energy and cold dark matter is considered. Evolution of a dark energy equation of state parameter is defined by a dark energy adiabatic sound speed and a dark sector interaction parameter, which must be more physically correct model then a previously used in which such evolution was given by some fixed dependence on scale factor. The constraints on interaction parameter and other parameters of the model was obtained using a cosmic microwave background, baryon acoustic oscillations and supernova SN Ia data.", "keyphrases": ["interacting dark energy", "dark matter", "cosmological perturbations"]}
{"id": "ritter2023amateur", "title": "From an amateur PN candidate to the Rosetta Stone of SN Iax research", "abstract": "On August 25th 2013 Dana Patchick from the \"Deep Sky Hunters\" (DSH) amateur astronomer group discovered a diffuse nebulosity in the Wide-field Infrared Survey Explorer (WISE) mid-IR image archive that had no optical counterpart but appeared similar to many Planetary Nebulae (PNe) in WISE. As his 30th discovery he named it Pa 30 and it was added to the HASH PN database as a new PN candidate. Little did he know how important his discovery would become. 10 years later this object is the only known bound remnant of a violent double WD merger accompanied by a rare Type Iax SN, observed and recorded by the ancient Chinese and Japanese in 1181 AD. This makes Pa 30 and its central star IRAS 00500+6713 (WD J005311) the only SN Iax remnant in our Galaxy, the only known bound remnant of any SN, and based on the central star's spectrum the only Wolf-Rayet star known that neither has a massive progenitor nor is the central star of a Planetary Nebula. We cover this story and our key role in it.", "keyphrases": ["emission nebulae", "supernova remnants", "type ia supernovae", "wolf-rayet stars"]}
{"id": "haileydunsheath2023characterization", "title": "Characterization of a Far-Infrared Kinetic Inductance Detector Prototype for PRIMA", "abstract": "The PRobe far-Infrared Mission for Astrophysics (PRIMA) is under study as a potential far-IR space mission, featuring actively cooled optics, and both imaging and spectroscopic instrumentation. To fully take advantage of the low background afforded by a cold telescope, spectroscopy with PRIMA requires detectors with a noise equivalent power (NEP) better than 1\u00d710\u221219 W Hz\u22121/2. To meet this goal we are developing large format arrays of kinetic inductance detectors (KIDs) to work across the 25\u2212250 micron range. Here we present the design and characterization of a single pixel prototype detector optimized for 210 micron. The KID consists of a lens-coupled aluminum inductor-absorber connected to a niobium interdigitated capacitor to form a 2 GHz resonator. We measure the performance of this detector with optical loading in the 0.01\u2212300 aW range. At low loading the detector achieves an NEP of 9\u00d710\u221220 W Hz\u22121/2 at a 10 Hz readout frequency, and the lens-absorber system achieves a good optical efficiency. An extrapolation of these measurements suggest this detector may remain photon noise limited at up to 20 fW of loading, offering a high dynamic range for PRIMA observations of bright astronomical sources.", "keyphrases": ["kinetic inductance detectors", "prima", "far-infrared", "ultra-low nep"]}
{"id": "bousder2023pulsar", "title": "Pulsar timing array results sheds light on Hubble tension during the end of inflation", "abstract": "Recently, pulsar timing array (PTA) collaborations, including NANOGrav, have reported evidence of a stochastic gravitational wave background within the nHz frequency range. It can be interpreted by gravitational waves from preheating era. In this context, we demonstrate that the emission of this stochastic gravitational wave background can be attributed to fluctuations occurring at the end of inflation, thus giving rise to the Hubble tension issue. At the onset of inflation, the value of the frequency of the gravitational wave signal stood at f=0.08nHz, but it rapidly transitioned to f=1nHz precisely at the end of inflation. However, just before the end of inflation, a phase characterized by curvature perturbation is known to occur, causing a swift increase in the frequency.", "keyphrases": ["pulsar timing array", "gravitational wave", "inflation", "hubble tension"]}
{"id": "jackson2023separateuniverse", "title": "The separate-universe approach and sudden transitions during inflation", "abstract": "The separate-universe approach gives an intuitive way to understand the evolution of cosmological perturbations in the long-wavelength limit. It uses solutions of the spatially-homogeneous equations of motion to model the evolution of the inhomogeneous universe on large scales. We show that the separate-universe approach fails on a finite range of super-Hubble scales at a sudden transition from slow roll to ultra-slow roll during inflation in the very early universe. Such transitions are a feature of inflation models giving a large enhancement in the primordial power spectrum on small scales, necessary to produce primordial black holes after inflation. We show that the separate-universe approach still works in a piece-wise fashion, before and after the transition, but spatial gradients on finite scales require a discontinuity in the homogeneous solution at the transition. We discuss the implications for the \u03b4N formalism and stochastic inflation, which employ the separate-universe approximation.", "keyphrases": ["cosmological perturbation theory", "inflation", "physics of the early universe", "primordial black holes"]}
{"id": "moskovitz2023photometry", "title": "Photometry of the Didymos system across the DART impact apparition", "abstract": "On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft impacted Dimorphos, the satellite of binary near-Earth asteroid (65803) Didymos. This demonstrated the efficacy of a kinetic impactor for planetary defense by changing the orbital period of Dimorphos by 33 minutes (Thomas et al. 2023). Measuring the period change relied heavily on a coordinated campaign of lightcurve photometry designed to detect mutual events (occultations and eclipses) as a direct probe of the satellite's orbital period. A total of 28 telescopes contributed 224 individual lightcurves during the impact apparition from July 2022 to February 2023. We focus here on decomposable lightcurves, i.e. those from which mutual events could be extracted. We describe our process of lightcurve decomposition and use that to release the full data set for future analysis. We leverage these data to place constraints on the post-impact evolution of ejecta. The measured depths of mutual events relative to models showed that the ejecta became optically thin within the first \u00a01 day after impact, and then faded with a decay time of about 25 days. The bulk magnitude of the system showed that ejecta no longer contributed measurable brightness enhancement after about 20 days post-impact. This bulk photometric behavior was not well represented by an HG photometric model. An HG1G2 model did fit the data well across a wide range of phase angles. Lastly, we note the presence of an ejecta tail through at least March 2023. Its persistence implied ongoing escape of ejecta from the system many months after DART impact.", "keyphrases": ["asteroids", "impact", "dart", "lightcurve photometry"]}
{"id": "barba2023optical", "title": "Optical properties of two complementary samples of intermediate Seyfert galaxies", "abstract": "We present preliminary results of the analysis of optical spectra of two complementary samples of Seyfert galaxies. The first sample was extracted from a selection of the 4th Fermi Gamma-ray Large Area Telescope (4FGL) catalog, and consists of 9 \u03b3-ray emitting jetted Seyfert galaxies. The second one was extracted from the Swift-BAT AGN Spectroscopic Survey (BASS), and is composed of 38 hard-X ray selected Active Galactic Nuclei (AGN). These two samples are complementary, with the former expected to have smaller viewing angles, while the latter may include objects with larger viewing angles. We measured emission line ratios to investigate whether the behavior of these Seyferts can be explained in terms of obscuration, as suggested by the well-known Unified Model (UM) of AGN, or if there are intrinsic differences due to the presence of jets, outflows, or the evolution. We found no indications of intrinsic differences. The UM remains the most plausible interpretation for these classes of objects even if some results can be challenging for this model.", "keyphrases": ["seyfert galaxies", "intermediate seyfert", "agn", "optical spectroscopy"]}
{"id": "hirling2023pyc2ray", "title": "pyC^2Ray: A flexible and GPU-accelerated Radiative Transfer Framework for Simulating the Cosmic Epoch of Reionization", "abstract": "Detailed modelling of the evolution of neutral hydrogen in the intergalactic medium during the Epoch of Reionization, 5\u2264z\u226420, is critical in interpreting the cosmological signals from current and upcoming 21-cm experiments such as Low-Frequency Array (LOFAR) and the Square Kilometre Array (SKA). Numerical radiative transfer codes offer the most physically motivated approach for simulating the reionization process. However, they are computationally expensive as they must encompass enormous cosmological volumes while accurately capturing astrophysical processes occurring at small scales (\u2272Mpc). Here, we present pyC2Ray, an updated version of the massively parallel ray-tracing and chemistry code, C2Ray, which has been extensively employed in reionization simulations. The most time-consuming part of the code is calculating the hydrogen column density along the path of the ionizing photons. Here, we present the Accelerated Short-characteristics Octhaedral RAytracing (ASORA) method, a ray-tracing algorithm specifically designed to run on graphical processing units (GPUs). We include a modern Python interface, allowing easy and customized use of the code without compromising computational efficiency. We test pyC2Ray on a series of standard ray-tracing tests and a complete cosmological simulation with volume size (349Mpc)3, mesh size of 2503 and approximately 106 sources. Compared to the original code, pyC2Ray achieves the same results with negligible fractional differences, \u223c10\u22125, and a speedup factor of two orders of magnitude. Benchmark analysis shows that ASORA takes a few nanoseconds per source per voxel and scales linearly for an increasing number of sources and voxels within the ray-tracing radii.", "keyphrases": ["radiative transfer", "epoch of reionization", "raytracing", "gpu methods", "21-cm", "cosmology", "intergalactic medium"]}
{"id": "byrne202321", "title": "21 cm Intensity Mapping with the DSA-2000", "abstract": "Line intensity mapping is a promising probe of the universe's large-scale structure. We explore the sensitivity of the DSA-2000, a forthcoming array consisting of over 2000 dishes, to the statistical power spectrum of neutral hydrogen's 21 cm emission line. These measurements would reveal the distribution of neutral hydrogen throughout the near-redshift universe without necessitating resolving individual sources. The success of these measurements relies on the instrument's sensitivity and resilience to systematics. We show that the DSA-2000 will have the sensitivity needed to detect the 21 cm power spectrum at z=0.5 and across power spectrum modes of 0.03-31.32 h/Mpc with 0.1 h/Mpc resolution. We find that supplementing the nominal array design with a dense core of 200 antennas will expand its sensitivity at low power spectrum modes and enable measurement of Baryon Acoustic Oscillations (BAOs). Finally, we present a qualitative discussion of the DSA-2000's unique resilience to sources of systematic error that can preclude 21 cm intensity mapping.", "keyphrases": ["cosmology", "h i line emission", "interferometry", "radio interferometry"]}
{"id": "bailerjones2023estimating", "title": "Estimating distances from parallaxes. VI: A method for inferring distances and transverse velocities from parallaxes and proper motions demonstrated on Gaia Data Release 3", "abstract": "The accuracy of stellar distances inferred purely from parallaxes degrades rapidly with distance. Proper motion measurements, when combined with some idea of typical velocities, provide independent information on stellar distances. Here I build a direction- and distance-dependent model of the distribution of stellar velocities in the Galaxy, then use this together with parallaxes and proper motions to infer kinegeometric distances and transverse velocities for stars in Gaia DR3. Using noisy simulations I assess the performance of the method and compare its accuracy to purely parallax-based (geometric) distances. Over the whole Gaia catalogue, kinegeometric distances are on average 1.25 times more accurate than geometric ones. This average masks a large variation in the relative performance, however. Kinegeometric distances are considerably better than geometric ones beyond several kpc, for example. On average, kinegeometric distances can be measured to an accuracy of 19", "keyphrases": ["catalogs", "bayesian statistics", "distance indicators", "stellar distances", "stellar motion", "astrometry", "parallax", "proper motions"]}
{"id": "talukdar2023constraining", "title": "Constraining primordial black hole masses through f(R) gravity scalarons in Big Bang Nucleosynthesis", "abstract": "Big Bang Nucleosynthesis (BBN) is a strong probe for constraining new physics including gravitation. f(R) gravity theory is an interesting alternative to general relativity which introduces additional degrees of freedom known as scalarons. In this work we demonstrate the existence of black hole solutions in f(R) gravity and develop a relation between scalaron mass and black hole mass. We have used observed bound on the freezeout temperature to constrain scalaron mass range by modifying the cosmic expansion rate at the BBN epoch. The mass range of primordial black holes (PBHs) which are astrophysical dark matter candidates is deduced. The range of scalaron mass which does not spoil the BBN era is found to be 10\u221216\u2212104 eV. The scalaron mass window 10\u221216\u221210\u221214 eV is consistent with the f(R) gravity PPN parameter derived from solar system experiments. The PBH mass range is obtained as 106\u221210\u221214 M\u2299. Scalarons constrained by BBN are also eligible to accommodate axion like dark matter particles. Estimation of deuterium (D) fraction and relative D+3He abundance in the f(R) gravity scenario shows that the BBN history mimics that of general relativity. While the PBH mass range is eligible for non-baryonic dark matter, the BBN bounded scalarons provide with an independent strong field test of f(R) gravity.", "keyphrases": ["modified gravity", "primordial black holes", "big bang nucleosynthesis", "dark matter theory"]}
{"id": "rose2023collisional", "title": "Collisional Shaping of Nuclear Star Cluster Density Profiles", "abstract": "A supermassive black hole (SMBH) surrounded by a dense, nuclear star cluster resides at the center of many galaxies. In this dense environment, high-velocity collisions frequently occur between stars. About 10", "keyphrases": ["stellar dynamics", "galactic center", "star clusters", "stellar mergers"]}
{"id": "liffman2023inviscid", "title": "Inviscid protostellar disc ring formation and high density ring edges due to the ejection and subsequent infall of material onto a protostellar disc", "abstract": "Discs of gas and dust are ubiquitous around protostars. Hypothetical disc viscosity is thought to cause the gas and dust to accrete onto the star. Turbulence within the disc might be the source of this disc viscosity. However, observed protostellar disc turbulence often appears to be small and not always conducive to disc accretion. In addition, theories for disc and planet evolution have difficulty in explaining the observed disc rings/gaps which form much earlier than expected. Protostellar accretion discs are observed to contain significant quantities of dust and pebbles. Observations show that some of this material is ejected from near the protostar, where it travels to the outer regions of the disc. Such solid infalling material has a relatively small amount of angular momentum compared to the material in the disc. This infalling material lowers the angular momentum of the disc and should drive a radial flow towards the protostar. We show that the local radial speed of the disc is proportional to the mass rate of infalling material onto the disc. Higher rates of infall onto the disc implies higher radial accretion disc speeds. As such, regions with high rates of infall will produce gaps on relatively short timescales in the disc, while regions associated with relative low rates of infalling material will produce disc rings. As such, the inner edge of a disc gap will tend to have a higher surface density, which may enhance the probability of planet formation. In addition, the outer edge of a disc gap will act as a dust trap and may become a site for planet formation. For the early Solar System, such a process may have collected O16-poor forsterite dust from the inner regions of the protosolar disc and O16-rich CAIs and AOAs from the inner edge regions of the protosolar disc, thereby constructing a region favourable to the formation of prechondritic planetesimals.", "keyphrases": ["planets", "protoplanetary disc", "meteorites"]}
{"id": "hosseini2023svr", "title": "SVR Algorithm as a Tool for More Optimal Intergalactic Medium Simulation in the Epoch of Reionization", "abstract": "All kinds of simulations of the intergalactic medium, such as hydrodynamic simulation, N-body simulation, numerical and semi-numerical simulation, etc., have been used to realize the history of this medium. One of these simulations is 21SSD, which is specifically focused on the epoch of reionization. This simulation deepens our understanding of the physics behind the intergalactic medium by considering the free parameters related to the Wouthuysen-Field coupling fluctuations and X-ray and Lyman line transfers in the intergalactic medium, and by presenting the plots of the power spectrum, brightness temperature, etc. in different redshifts. However, due to many physical phenomena that play significant roles in this epoch, simulations of the intergalactic medium are usually extremely complex, time-consuming, and require very powerful hardware. In this work, by using the Support Vector Regression algorithm and based on the 21SSD simulation datasets, we have tried to make the machine fully understand the brightness temperature changes in terms of redshift for different astrophysical free parameters values. At first, we trained the machine with the results of the 21SSD simulation. Then, the machine was able to predict the brightness temperature in terms of redshift with very high accuracy for other interval coefficients. Although we have used this algorithm to estimate the brightness temperature, it seems that this algorithm can be easily used for other parts of cosmology and astrophysics. With its help, it is possible to save time and obtain results with extraordinary accuracy similar to complex simulations, even with normal hardware.", "keyphrases": ["hydrodynamic simulation", "21ssd simulation", "intergalactic medium thermal history", "epoch of reionization", "machine learning"]}
{"id": "columba2023disk", "title": "Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): HD 34700 A unveils an inner ring", "abstract": "Context. The study of protoplanetary disks is fundamental to understand their evolution and interaction with the surrounding environment, and to constrain planet formation mechanisms. Aims. We aim at characterising the young binary system HD 34700 A, which shows a wealth of structures. Methods. Taking advantage of the high-contrast imaging instruments SPHERE at the VLT, LMIRCam at the LBT, and of ALMA observations, we analyse this system at multiple wavelengths. We study the rings and spiral arms morphology and the scattering properties of the dust. We discuss the possible causes of all the observed features. Results. We detect for the first time, in the H\u03b1 band, a ring extending from \u223c65 au to \u223c120 au, inside the ring already known from recent studies. These two have different physical and geometrical properties. Based on the scattering properties, the outer ring may consist of grains of typical size aout>4\u03bcm, while the inner ring of smaller grains (ain<=0.4\u03bcm). Two extended logarithmic spiral arms stem from opposite sides of the disk. The outer ring appears as a spiral arm itself, with a variable radial distance from the centre and extended substructures. ALMA data confirm the presence of a millimetric dust substructure centred just outside the outer ring, and detect misaligned gas rotation patterns for HD 34700 A and B. Conclusions. The complexity of HD 34700 A, revealed by the variety of observed features, suggests the existence of one or more disk-shaping physical mechanisms. Possible scenarios, compatible with our findings, involve the presence inside the disk of a yet undetected planet of several Jupiter masses and the system interaction with the surroundings by means of gas cloudlet capture or flybys. Further observations with JWST/MIRI or ALMA (gas kinematics) could shed more light on these.", "keyphrases": ["protoplanetary disks", "intermediate-mass stars", "planet formation", "multiple systems", "direct imaging"]}
{"id": "hu2023optical", "title": "How can the optical variation properties of active galactic nuclei be unbiasedly measured?", "abstract": "The variability of active galactic nuclei (AGNs) is ubiquitous but has not yet been understood. Measuring the optical variation properties of AGNs, such as variation timescale and amplitude, and then correlating them with their fundamental physical parameters, have long served as a critical way of exploring the origin of AGN variability and the associated physics of the accretion process in AGNs. Obtaining accurate variation properties of AGNs is thus essential. It has been found that the damped random walk (DRW) process can well describe the AGN optical variation, however, there is a controversy over how long a minimal monitoring baseline is required to obtain unbiased variation properties. In this work, we settle the controversy by exhaustively scrutinizing the complex combination of assumed priors, adopted best-fit values, ensemble averaging methods, and fitting methods. Then, the newly proposed is an optimized solution where unbiased variation properties of an AGN sample possessing the same variation timescale can be obtained with a minimal baseline of about 10 times their variation timescale. Finally, the new optimized solution is used to demonstrate the positive role of time domain surveys to be conducted by the Wide Field Survey Telescope in improving constraints on AGN variation properties.", "keyphrases": ["active galactic nuclei", "time domain", "optical variability"]}
{"id": "arya2023modified", "title": "A modified lognormal approximation of the Lyman-\u03b1 forest: comparison with full hydrodynamic simulations at 2\u2264 z\u2264 2.7", "abstract": "Observations of the Lyman-\u03b1 forest in distant quasar spectra with upcoming surveys are expected to provide significantly larger and higher-quality datasets. To interpret these datasets, it is imperative to develop efficient simulations. One such approach is based on the assumption that baryonic densities in the intergalactic medium (IGM) follow a lognormal distribution. We extend our earlier work to assess the robustness of the lognormal model of the Lyman-\u03b1 forest in recovering the parameters characterizing IGM state, namely, the mean-density IGM temperature (T_0), the slope of the temperature-density relation (\u03b3), and the hydrogen photoionization rate (\u0393_12), by comparing with high-resolution Sherwood SPH simulations across the redshift range 2 \u2264 z \u2264 2.7. These parameters are estimated through a Markov Chain Monte Carlo technique, using the mean and power spectrum of the transmitted flux. We find that the usual lognormal distribution of IGM densities cannot recover the parameters of the SPH simulations. This limitation arises from the fact that the SPH baryonic density distribution cannot be described by a simple lognormal form. To address this, we extend the model by scaling the linear density contrast by a parameter \u03bd. While the resulting baryonic density is still lognormal, the additional parameter gives us extra freedom in setting the variance of density fluctuations. With this extension, values of T_0 and \u03b3 implied in the SPH simulations are recovered at \u223c 1-\u03c3 (\u2272 10", "keyphrases": ["intergalactic media", "lyman-\u03b1 forest", "power spectrum"]}
{"id": "liu2023quasi2d", "title": "Quasi-2D Weak Lensing Cosmological Constraints Using the PDF-SYM method", "abstract": "Cosmic shear statistics, such as the two-point correlation function (2PCF), can be evaluated with the PDF-SYM method instead of the traditional weighted-sum approach. It makes use of the full PDF information of the shear estimators, and does not require weightings on the shear estimators, which can in principle introduce additional systematic biases. This work presents our constraints on S_8 and \u03a9_m from the shear-shear correlations using the PDF-SYM method. The data we use is from the z-band images of the Dark Energy Camera Legacy Survey (DECaLS), which covers about 10000 deg^2 with more than 100 million galaxies. The shear catalog is produced by the FQ method, and well tested on the real data itself with the field-distortion effect. Our main approach is called quasi-2D as we do use the photo-z information of each individual galaxy, but without dividing the galaxies into redshift bins. We mainly use galaxy pairs within the redshift interval between 0.2 and 1.3, and the angular range from 4.7 to 180 arcmin. Our analysis yields S_8=0.762 \u00b1 0.026 and \u03a9_m=0.234 \u00b1 0.075, with the baryon effects and the intrinsic alignments included. The results are robust against redshift uncertainties. We check the consistency of our results by deriving the cosmological constaints from auto-correlations of \u03b3_1 and \u03b3_2 separately, and find that they are consistent with each other, but the constraints from the \u03b3_1 component is much weaker than that from \u03b3_2. It implies a much worse data quality of \u03b3_1, which is likely due to additional shear uncertainties caused by CCD electronics (according to the survey strategy of DECaLS). We also perform a pure 2D analysis, which gives S_8=0.81^+0.03_-0.04 and \u03a9_m=0.25^+0.06_-0.05. Our findings demonstrate the potential of the PDF-SYM method for precision cosmology.", "keyphrases": ["weak lensing", "shear-shear correlations", "cosmological parameters", "observations", "analysis"]}
{"id": "kareta2023ejecta", "title": "Ejecta Evolution Following a Planned Impact into an Asteroid: The First Five Weeks", "abstract": "The impact of the DART spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos' orbit substantially, largely from the ejection of material. We present results from twelve Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days after impact. After an initial brightening of \u00a01.4 magnitudes, we find consistent dimming rates of 0.11-0.12 magnitudes/day in the first week, and 0.08-0.09 magnitudes/day over the entire study period. The system returned to its pre-impact brightness 24.3-25.3 days after impact through the primary ejecta tail remained. The dimming paused briefly eight days after impact, near in time to the appearance of the second tail. This was likely due to a secondary release of material after re-impact of a boulder released in the initial impact, through movement of the primary ejecta through the aperture likely played a role.", "keyphrases": ["asteroids", "planetary defence", "dart", "dust"]}
{"id": "kenworthy2023planetary", "title": "A planetary collision afterglow and transit of the resultant debris cloud", "abstract": "Planets grow in rotating disks of dust and gas around forming stars, some of which can subsequently collide in giant impacts after the gas component is removed from the disk. Monitoring programs with the warm Spitzer mission have recorded significant and rapid changes in mid-infrared output for several stars, interpreted as variations in the surface area of warm dusty material ejected by planetary-scale collisions and heated by the central star: e.g., NGC 2354-ID8, HD 166191 and V844 Persei. Here we report combined observations of the young (about 300 Myr), solar-like star ASASSN-21qj: an infrared brightening consistent with a blackbody temperature of 1000 K and a luminosity of 4 percent of that of the star lasting for about 1000 days, partially overlapping in time with a complex and deep wavelength-dependent optical eclipse that lasted for about 500 days. The optical eclipse started 2.5 years after the infrared brightening, implying an orbital period of at least that duration. These observations are consistent with a collision between two exoplanets of several to tens of Earth masses at 2 to 16 au from the central star. Such an impact produces a hot, highly-extended post-impact remnant with sufficient luminosity to explain the infrared observations. Transit of the impact debris, sheared by orbital motion into a long cloud, causes the subsequent complex eclipse of the host star.", "keyphrases": ["exoplanets", "planet formation", "debris disks"]}
{"id": "wang2023floating", "title": "Floating binary planets from ejections during close stellar encounters", "abstract": "The discovery of planetary systems beyond our solar system has posed challenges to established theories of planetary formation. Planetary orbits display a variety of architectures not predicted by first principles, and free-floating planets appear ubiquitous. The recent discovery of candidate Jupiter Mass Binary Objects (JuMBOs) by the James Webb Space Telescope (JWST) further expanded this enigma. Here, by means of high-accuracy, direct N-body simulations, we evaluate the possibility that JuMBOs may form as a result of ejection after a close stellar flyby. We consider a system of two Jupiter-like planets moving in circular orbits with velocities v_1 and v_2 at distances a_1 and a_2 around a Sun-like star. The interloper is another Sun-like star approaching with asymptotic velocity v_\u221e. We find that JuMBOs can indeed be formed upon ejection if the two planets are nearly aligned as the interloper reaches the closest approach. The ratio of the cross section of JuMBOs production to that of single ejected free-floating planets can approach \u223c 20% for v_\u221e/v_2 \u223c 0.1 - 0.2 and a_1/a_2\u223c 0.75-0.8. JuMBOs formed via this channel are expected to have an average semi-major axis comparable to \u0394 a = (a_2-a_1) and high eccentricity, with a distinctive superthermal distribution which can help to observationally identify this formation channel and distinguish it from primordial formation. If the ejection channel is confirmed for these or future JWST observations, these JuMBOs will directly inform us of the conditions where these giant planets formed in protoplanetary disks, putting stringent constraints on the giant planet formation theory.", "keyphrases": ["planetary systems", "simulations", "dynamics"]}
{"id": "tominaga2023rapid", "title": "Rapid Dust Growth During Hydrodynamic Clumping Due to Streaming Instability", "abstract": "Streaming instability is considered to be one of the dominant processes to promote planetesimal formation by gravitational collapse of dust clumps. The development of streaming instability is expected to form dust clumps in which the local dust density is strongly enhanced and even greater than the Roche density. The resulting clumps can collapse to form planetesimals. Recent simulations conducted long-term simulations and showed that such strong clumping occurs in a wider parameter space than previously expected. However, the indicated timescale for strong clumping can be on the order of tens to hundreds Keplerian periods. In this paper, we estimate the growth time of dust grains during the pre-clumping phase. We find that the dust growth considerably proceeds before the strong clumping because even the moderate clumping due to streaming instability increases the local dust-to-gas ratio \u227310. Depending on the gas sound speed, the dust collision velocity can be kept below \u223c 1 m/s once sufficiently strong dust clumping occurs. Thus, even silicate grains might have the potential to grow safely toward the size whose Stokes number is unity during the clumping. Our results demonstrate the importance of local dust coagulation during the dust clumping due to streaming instability.", "keyphrases": ["hydrodynamics", "instabilities", "protoplanetary disks"]}
{"id": "kanwar2023hydrocarbon", "title": "Hydrocarbon chemistry in inner regions of planet forming disks", "abstract": "The analysis of the mid-infrared spectra helps understanding the composition of the gas in the inner, dense and warm terrestrial planet forming region of disks around young stars. ALMA has detected hydrocarbons in the outer regions of the planet forming disk and Spitzer detected C2H2 in the inner regions. JWST- MIRI provides high spectral resolution observations of C2H2 and a suite of more complex hydrocarbons are now reported. Interpreting the fluxes observed in the spectra is challenging and radiation thermo-chemical codes are needed to properly take into account the disk structure, radiative transfer, chemistry and thermal balance. Various disk physical parameters like the gas-to-dust ratio, dust evolution including radial drift, dust growth and settling can affect the fluxes observed in the mid-IR. Still, thermo-chemical disk models were not always successful in matching all observed molecular emission bands simultaneously. The goal of this project is two-fold. We analyse the warm carbon chemistry in the inner regions of the disk, i.e. within 10 au to find pathways forming C2H2 potentially missing from the existing chemical networks. Second, we analyse the effect of the new chemistry on the line fluxes of acetylene. We use radiative thermo-chemical disk code PRODIMO to expand the hydrocarbon chemistry that occurs in a typical standard T Tauri disks. We used the UMIST and the KIDA rate databases for collecting reactions for the species. We include a number of three-body and thermal decomposition reactions from STAND2020 network. We included isotopomers for the species that were present in the databases. The chemistry is then analysed in the regions that produce observable features in the mid-infrared spectra. The effect of expanding the hydrocarbon chemistry on the mid-infrared spectra is studied. Acetylene is formed via two ....", "keyphrases": ["astrochemistry", "inner disk", "hydrocarbons", "mid-ir spectra", "jwst-miri"]}
{"id": "dubovichenko2023reaction", "title": "The reaction rate of radiative n 8Li capture in the range from 0.01 to 10 T 9", "abstract": "Within the modified potential cluster model (MPCM) with forbidden states, the total cross sections are calculated for capture in the ground and first excited states of the 9Li nucleus in the n8Li channel in the energy range from 10\u22125 eV to 5 MeV based on \u04151 and M1 transitions. The experimentally proved resonance at Ec.m. = 0.232 MeV in the 4P5/2 wave and ab initio-predicted 4P3/2 resonance at 1.32 MeV [Phys. Rev. C 103, 035801 (2021)] are considered. The strong impact of the asymptotic constant and channel spectroscopic factors on the total capture cross sections are responsible for the variation in the absolute values within factor two. As a consequence, the thermal cross sections are (Formula presented.) 24\u201346.8 mb. The evaluation of (Formula presented.) based on the extrapolation of ab initio cross sections yields \u223c85 mb. The reaction rate is calculated in the temperature range from 0.01 to 10 T9. The reported reaction rates are compared at the benchmark point 1 T9. The comparison of two datasets [Phys. Rev. C 103, 035801 (2021) and Phys. Rev. C 105, 064608 (2022)] on reaction rates recently calculated in microscopic models in extended temperature intervals shows the essential quantitative and qualitative differences. The comparative joint analysis of the reaction rates of radiative neutron capture on the lithium isotopes 6,7,8Li is suggested for the choice of an optimal interval for the asymptotic constants.", "keyphrases": ["cluster model", "n<sup>8</sup>li system", "nuclear astrophysics", "reaction rate", "thermal and astrophysical energies", "total cross sections"]}
{"id": "m\u00f6bius2023how", "title": "How catching the interstellar wind in the inner solar system led the way on a road to interdisciplinary research between heliophysics and astrophysics", "abstract": "Combined in situ observations of the interstellar wind through the solar system and of its pickup ions (PUIs), implanted after ionization in the solar wind, explain, in comparison with interstellar absorption lines of nearby stars, that the Sun is in an interaction region of the two nearest interstellar clouds. This new finding disrupts the long-held understanding that we are inside the local interstellar cloud (LIC). We discuss how space physics evolved toward such interdisciplinary studies between heliophysics and astrophysics. In 1984, the discovery of interstellar He+ PUIs exposed the very local interstellar medium to in situ diagnostics at 1AU. These PUIs provide the interstellar gas composition and form a stepping stone for the acceleration of ions, especially into anomalous cosmic rays. Using the Sun as a gravitational spectrograph, direct imaging of the neutral interstellar wind, first for He and then for H, O, and Ne, provides the interstellar gas velocity vector and temperature at the heliopause. Combining the interstellar gas flow vectors, those of secondary neutral He and O, and the interstellar magnetic field direction deduced from the interstellar H deflection and termination shock anisotropy seen by the Voyagers provides synergistically the heliosphere\u2019s shape, its interaction with the interstellar medium, and constrains our radiation environment. This ISMF organizes the bright Ribbon seen in all-sky images of energetic neutral atoms with the potential to provide its precision determination. The elemental and isotopic composition from PUI and neutral gas observations constrains the galactic evolution and Big Bang cosmology, opening additional interdisciplinary opportunities.", "keyphrases": ["energetic neutral atoms", "heliosphere boundary", "interstellar gas composition", "interstellar gas flow", "interstellar magnetic field", "pickup ions"]}
{"id": "song2023mechanism", "title": "A mechanism of the auroral substorm expansion onset: electric discharge in the double layer", "abstract": "Magnetospheric substorms often occur when a significant amount of energy from the solar wind is deposited and stored in the magnetotail during the growth phase and release explosively in the expansion phase, which accelerates charged particles causing the rapid auroral intensification. A physical mechanism is needed to release the energy explosively. The formation of double layers is a likely mechanism for the energy release and the acceleration of particles and triggers the onset of the expansion phase. We suggest that the localized parallel electric field that forms the double layer results from the displacement current complying with Ampere\u2019s law for the dynamic case. The double layers are embedded in low density cavities surrounded by enhanced magnetic stresses. Positive feedback in the electric field generation may cause rapid release of the accumulated energy. The Poynting flux carried by Alfven waves continuously supplies the energy to maintain strong electric fields during the rapid development of auroral substorms.", "keyphrases": ["auroral substorm", "displacement current", "double layer", "parallel electric field", "substorm onset"]}
{"id": "garofalo2023counter", "title": "Counter-rotating black holes from FRII lifetimes", "abstract": "Estimates suggest that while FRII jets appear to have lifetimes constrained to hundreds of millions of years, radio galaxies with FRI jets appear to be longer lived. We illustrate the nature of this time constraint from model perspectives, showing how compatibility between theory and data match in a way suggesting a key difference between active galaxies whose engines are characterized by accretion onto co-rotating versus counter-rotating black holes. We calculate a range of timescales for counter-rotating black holes for a range of accretion rates compatible with theory which we then compare to data. The validity of these timescales constitutes the most powerful recent piece of evidence for considering counter-rotation between black holes and accretion disks in high energy astrophysics.", "keyphrases": ["black holes", "counter-rotating black holes", "fri/frii dichotomy", "jets from active galaxies", "radio galaxies and quasars"]}
{"id": "nitta2023solar", "title": "Solar activities associated with 3He-rich solar energetic particle events observed by Solar Orbiter", "abstract": "A series of 3He-rich solar energetic particle (SEP) events was observed by Solar Orbiter in May 2021 at a radial distance of 0.95 AU. An isolated active region AR 12824 was likely the ultimate source of these SEP events. The period of the enhanced flux of 3He was also a period of frequent type III bursts in the decametric-hectometric range, confirming their close relationship. As in past studies, we try to find the solar activities possibly responsible for 3He-rich SEP events, using the type III bursts close to the particle injection times estimated from the velocity dispersion. But this exercise is not as straightforward as in many of the past studies since the region produced many more type III bursts and jet-like eruptions than the SEP injections. We may generalize the solar activities for the 3He-rich SEP events in question as coronal jets, but their appearances do not necessarily conform to classic jets that consist of a footpoint and a spire. Conversely, such jets often did not accompany type III bursts. The areas that produced jet-like eruptions changed within the active region from the first to the second set of 3He-rich SEP events, which may be related to the extended coronal mass ejection that launched stealthily.", "keyphrases": ["elemental abundances", "radio emission", "solar energetic particles", "solar jets", "sun", "uv radiation"]}
{"id": "vavry\u010duk2023gravitational", "title": "Gravitational orbits in the expanding Universe revisited", "abstract": "Modified Newtonian equations for gravitational orbits in the expanding Universe indicate that local gravitationally bounded systems like galaxies and planetary systems are unaffected by the expansion of the Universe. This result is derived for the space expansion described by the standard FLRW metric. In this paper, the modified Newtonian equations are derived for the space expansion described by the conformal cosmology (CC) metric. In this metric, the comoving and proper times are different similarly as the comoving and proper distances. As shown by Vavry\u010duk (Front. Phys. 2022), this metric is advantageous, because it properly predicts the cosmic time dilation, and fits the Type Ia supernova luminosity observations with no need to introduce dark energy. Surprisingly, the solution of the equations for gravitational orbits based on the CC metric behaves quite differently than that based on the FLRW metric. In contrast to the common opinion that local systems resist the space expansion, they expand according to the Hubble flow in the CC metric. The evolution of the local systems with cosmic time is exemplified on numerical modelling of spiral galaxies. The size of the spiral galaxies grows consistently with observations and a typical spiral pattern is well reproduced. The theory predicts flat rotation curves without an assumption of dark matter surrounding the galaxy. The theory resolves challenges to the \u039bCDM model such as the problem of faint satellite galaxies, baryonic Tully-Fisher relation or the radial acceleration relation. Furthermore, puzzles in the solar system are successfully explained such as the Faint young Sun paradox or the Moon\u2019s and Titan\u2019s orbit anomalies.", "keyphrases": ["conformal metric", "cosmic time dilation", "cosmological redshift", "dark energy", "dark matter", "galaxy expansion", "rotation curves", "winding problem"]}
{"id": "cucho_padin2023exospy", "title": "EXOSpy: A python package to investigate the terrestrial exosphere and its FUV emission", "abstract": "The exosphere is the uppermost layer of the terrestrial atmosphere, mainly composed of atomic hydrogen (H) that resonantly scatters solar far-ultraviolet (FUV) photons at 121.56 nm, also referred to as Lyman-Alpha (Ly-\u03b1) emission. Analysis of this emission has been used to determine the global, three-dimensional, and time-dependent exospheric H density structure, which is essential to assess the permanent escape of H to space as well as to determine their role in governing the transient response of terrestrial plasma environment to space weather. Thus, Ly-\u03b1 emission and its by-product, the H density, are highly desirable to the magnetospheric community. On the other hand, this emission can also be regarded as a significant source of contamination during studies of FUV targets such as O/B-type stars, planetary and exoplanetary atmospheres, and the circumgalactic medium, especially when observations are acquired from Earth-orbiting instruments. In this case, accurate specification of exospheric Ly-\u03b1 photon flux and its subsequent removal is required by the planetary and astrophysics community studying solar/extra-solar system objects. This work introduces EXOSpy, an open-source python-based package that provides several models of terrestrial exospheric H density and calculates exospheric Ly-\u03b1 emission with a high potential to contribute to investigations in both communities. We present several examples to demonstrate how EXOSpy can be used to (i) validate current and new exospheric models based on actual Ly-\u03b1 radiance data, (ii) estimate exospheric contamination for a given instrument\u2019s line-of-sight and spatial location, and (iii) provide support for new space-based FUV instrument design.", "keyphrases": ["atomic hydrogen", "fuv", "lyman-alpha", "python", "terrestrial exosphere"]}
{"id": "kozak2023turbulent", "title": "Turbulent dipolarization regions in the Earth\u2019s magnetotail: ion fluxes and magnetic field changes", "abstract": "In this work, we consider the dynamics of ion fluxes and magnetic field changes in turbulent regions of magnetotail dipolarizations. The data from the Cluster-II mission (magnetic field measurements from fluxgate magnetometers and energetic charged particle observations from RAPID spectrometers) were used for the analysis. We study individual events and investigate statistically the changes of charged particle fluxes during magnetic field dipolarizations observed during 2001\u20132015. Received changes in the spectral index indicate that CNO+ ions undergo stronger acceleration during dipolarization than protons and helium ions. Before dipolarization front monotonic growth the ions flux is observed (the maximum of flux is observed at 1\u20131,5 min after the start of dipolarization) in the range of \u223c 92\u2013374 keV for proton; in the energy range \u223c 138\u2013235 keV for He+ and in the energy range of 414\u2013638 keV for CNO+ ions. Flux increase before arriving dipolarization front may result from the reflection of plasma sheet ions at the dipolarization front and the result of the resonant interactions of ions with low-frequency electromagnetic waves.", "keyphrases": ["charged particles", "differential fluxes", "dipolarization fronts", "superimposed epoch analysis", "waves"]}
{"id": "korzennik2023precision", "title": "Precision and systematic errors in global helioseismology mode fitting and inversions: Leveraging some 25 years of nearly uninterrupted observations", "abstract": "We have on hand some 25 years of nearly uninterrupted high-quality and high-cadence global helioseismic data. The Global Oscillations Network Group (GONG) project has been producing science quality data since 1995, the Michelson Doppler Imager (MDI) started in 1996, and the Helioseismic and Magnetic Imager (HMI) took over in 2010. Fundamental new constraints have been imposed by helioseismic inferences, yet global helioseismology data processing seems somewhat frozen in time for some of its methodologies. I review and discuss some specific aspects of global helioseismology data analysis, with an emphasis on the issues and challenges presented by mode fitting and inversion techniques. I compare and contrast results derived by different fitting methods, whether using different techniques, different lengths of time series, or different fitting parameters, like leakage matrices or the inclusion or omission of the mode profile asymmetry, leading to our current best handle on the residual systematic errors.", "keyphrases": ["inverse modeling", "mode fitting", "sun", "sun\u2014helioseismology", "sun\u2014interior"]}
{"id": "hu2023burst", "title": "The burst observer and optical transient exploring system in the multi-messenger astronomy era", "abstract": "The Burst Observer and Optical Transient Exploring System (BOOTES) was first designed as an asset of autonomous telescopes that started to be deployed in 1998, taking 24 years to be fully developed around the earth. Nowadays BOOTES has became a global network of robotic telescopes, being the first one present in all continents, as of 2022. Here we present the details of the network and review its achievements over the last 2 decades regarding follow-up observations of high-energy transient events. Moreover, considering the recent operations of neutrino and gravitational wave detectors, some hot-topic expectations related to robotic astronomy are discussed within the framework of multi-wavelength astrophysics.", "keyphrases": ["bootes network", "multi-messenger", "optical observations", "robotic astronomy", "telescopes"]}
{"id": "hort\u00faa2023constraining", "title": "Constraining cosmological parameters from N-body simulations with variational Bayesian neural networks", "abstract": "Introduction: Methods based on deep learning have recently been applied to recover astrophysical parameters, thanks to the ability of these techniques to capture information from complex data. One of these schemes is the approximate Bayesian neural network (BNN), which has demonstrated to yield a posterior distribution into the parameter space that is extremely helpful for uncertainty quantification. However, modern neural networks tend to produce overly confident uncertainty estimates and introduce bias when applying BNNs to data. Method: In this work, we implement multiplicative normalizing flows (MNFs), a family of approximate posteriors for the parameters of BNNs with the purpose of enhancing the flexibility of the variational posterior distribution, to extract \u03a9m, h, and \u03c38 from the QUIJOTE simulations. We compared the latter method with the standard BNNs and the Flipout estimator. Results: We have found that the use of MNFs consistently outperforms the standard BNNs with a percent difference in the mean squared error of 21", "keyphrases": ["artificial intelligence", "cosmology", "deep neural networks", "n-body simulations", "parameter estimation"]}
{"id": "saleem2023collapsing", "title": "Collapsing cylindrically symmetric filamentary stellar object", "abstract": "This work investigates the collapsing behavior of filamentary objects under the influence of dark matter. For this purpose, we use f(R, T) gravity as a candidate for dark matter. The collapse equation is obtained by imposing the Darmois junction condition at the collapsing boundary. At the collapsing boundary, it is observed that the radial pressure is non-zero and is proportional to the field time-dependent component. Finally, we check the relationship between gravitational waves and dark source terms. It is concluded that the dark source terms disrupt the propagation of gravitational waves.", "keyphrases": ["compact stellar filament", "dark matter", "f(r", "t) gravity", "gravitational collapse", "gravitational waves"]}
{"id": "rindler_daller2023particle", "title": "On particle scattering in Gross-Pitaevskii theory and implications for dark matter halos", "abstract": "Bose-Einstein-condensed dark matter (BEC-DM), also called scalar field dark matter (SFDM), has become a popular alternative to the standard, collisionless cold dark matter (CDM) model, due to its long-held potential to resolve the small-scale crisis of CDM. Halos made of BEC-DM have been modelled using the Gross-Pitaevskii (GP) equation coupled to the Poisson equation; the so-called GPP equations of motion. These equations are based on fundamental microphysical conditions that need to be fulfilled in order for the equations to be valid in the first place, related to the diluteness of the DM gas and the nature of the particle scattering model. We use these conditions in order to derive the implications for the BEC-DM parameters, the 2-particle self-interaction coupling strength g and the particle mass m. We compare the derived bounds with the constraint that results from the assumption of virial equilibrium of the central cores of halos, deriving a relationship that connects g and m. We find that the GPP conditions are greatly fulfilled, for BEC-DM particle masses of interest, if such models also obey the virial condition that turns out to be the strongest constraint. We also derive the implications for the elastic scattering cross section (per particle mass) in BEC-DM halos, based on the scattering model of GPP, and find a huge range of possible values, depending on the self-interaction regime. We put our results into context to recent literature which predicts sub-kpc core size in BEC-DM halos.", "keyphrases": ["bose-einstein-condensed dark matter", "cosmology", "galactic halos", "gross-pitaevskii theory", "particle scattering"]}
{"id": "dialynas2023future", "title": "A future interstellar probe on the dynamic heliosphere and its interaction with the very local interstellar medium: In-situ particle and fields measurements and remotely sensed ENAs", "abstract": "The recently published Interstellar Probe (ISP) study report describes a pragmatic mission concept with a launch window that starts in 2036 and is expected to reach several hundreds of astronomical units past the heliopause within a time frame of \u226550 years (https://interstellarprobe.jhuapl.edu/Interstellar-Probe-MCR.pdf). Following the ISP report, this paper, that will also be accessible from the Bulletin of the AAS (BAAS) in the framework of the Decadal Survey for Solar and Space Physics (Heliophysics) 2024\u20132033 (Dialynas et al., A future Interstellar Probe on the dynamic heliosphere and its interaction with the very local interstellar medium: In-situ particle and fields measurements and remotely sensed ENAs, 2022a), aims to highlight the importance of studying the physics of the interactions pertaining to the expanding solar wind that meets the plasma, gas and dust flows of the very local interstellar medium, forming the complex and vast region of our astrosphere. We focus on three fundamental open science questions that reveal the dynamical nature of the heliosphere A) Where are the heliosphere boundaries and how thick is the heliosheath B) Is there a \u201cmissing\u201d pressure component towards exploring the dynamics of the global heliosheath and its interaction with the very local interstellar medium C) Why does the shape and size of the global heliosphere appear different in different Energetic Neutral Atom energies? We argue that these questions can only be addressed by exploiting a combination of in-situ charged particle, plasma waves and fields measurements with remotely sensed Energetic Neutral Atoms that can be measured simultaneously from the instruments of a future Interstellar Probe mission, along its trajectory from interplanetary space through the heliosheath and out to the very local interstellar medium.", "keyphrases": ["cassini", "energetic neutral atoms", "heliosheath", "heliosphere", "interstellar probe", "solar wind", "very local interstellar medium", "voyager"]}
{"id": "cooper2023lunar", "title": "Lunar Solar Occultation Explorer (LunaSOX)", "abstract": "In the present decade and beyond, now 51 years after the last Apollo landing, the NASA Artemis human exploration program will offer abundant opportunities for heliophysics investigations from, by, and of the Moon from the vantage points of the lunar orbit and the surface. The Lunar Solar Occultation Explorer (LunaSOX) concept uses the lunar limb to occult the solar disk for high-resolution coronal observations at hourly, daily, to biweekly cadences from spacecraft either in the lunar orbit or at the surface. A 0.2 m diameter solar telescope in orbit with white light and narrow-band visible filters would provide arcsecond spectroscopic imaging of the low-to-high corona (1\u201310 R\u2609) with an upper limit of 10\u201312 B\u2609 on the local scattered light background from lunar atmospheric dust, as compared to 10\u20139 B\u2609 for Earth ground-based solar eclipse observations looking up through the atmosphere at totality. For eclipse observations from and by the Moon, there would be no significant atmospheric disturbances that otherwise limit seeing to arcsec resolution from Earth\u2019s surface. The present eccentric orbits of the ARTEMIS P1 and P2 spacecraft are used as models for a 1 \u00d7 10 Rm orbit of LunaSOX to compute the times of solar eclipse intervals, up to 2 hours in duration between the east and west solar hemispheres at a daily cadence for coronal observations at 1\u201316 R\u2609 when the orbital aposelene is in anti-sunward directions. In a low-altitude circular orbit and from the surface, the observational cadences would, respectively, be hourly and biweekly. LunaSOX satellites also carrying in situ space environment instruments could integrate into a network of orbital platforms for space weather monitoring and communications relay to far-side surface lander and permanent base sites, e.g., for low-frequency radio cosmology and detection of exoplanet magnetospheres.", "keyphrases": ["heliophysics", "moon", "solar corona", "solar eclipse", "solar wind"]}
{"id": "linsky2023creating", "title": "Creating a new paradigm for the local interstellar medium\u2013A perspective", "abstract": "The interstellar medium close to the Sun called the local ISM (LISM) provides critical insights into physical processes and phenomena in the more distant interstellar medium in our Galaxy without the confusion of many complex structures in the sight lines to distant stars. High-resolution ultraviolet spectra are powerful diagnostic tools for understanding the LISM together with the observed properties of the outer heliosphere and hydrogen wall absorption in the astrospheres of nearby stars. For nearly 30 years the kinematic structure of the LISM has been identified from measured radial velocities of interstellar gas along many sight lines distributed across a wide range of Galactic coordinates. These data permitted the identification of three dimensional velocity vectors characterizing \u201cclouds\u201d. While this simple structure robustly predicts the radial velocities and associated clouds along newly observed sight lines, there are many challenges to this multi-cloud model that could lead to a revised model of the LISM. This paper reviews the assumptions and accomplishments of the multi-cloud model, and describes how the various challenges to this model could lead to a more comprehensive model with insight into physical processes and structures in the Galactic interstellar medium.", "keyphrases": ["heliopause (707)", "heliosphere (711)", "interstellar clouds (834)", "interstellar medium wind (848)", "stellar-interstellar interactions (1576)", "ultraviolet sources (1741)", "warm neutral medium (1789)"]}
{"id": "caliskan2023structural", "title": "Structural properties of a new class of stellar structures in modified teleparallel gravity", "abstract": "This paper explores new neutron star models based on spherically symmetric space\u2013time. We take into account the gravitational effects of (Formula presented.) gravity, in which T is the torsion and (Formula presented.) is the trace of the energy\u2013momentum tensor. Field equations are evaluated by incorporating the off-diagonal tetrad. In this paper, we discuss the detailed properties of compact star candidates 4U1538\u201352, J0437\u20134,715, J0030 + 0451, and 4U1820\u201330, like energy density, pressure profiles, gradients, anisotropy, energy conditions, equation of state, speeds of sound, TOV equation, and compactification parameters. We discuss all these characteristics using the quadratic cosmological model of (Formula presented.) gravity. We use the well-famed junction equations to evaluate the unknown parameters. Our detailed and comprehensive graphical analysis ensures that the model containing the anisotropic nature of stellar structures is physically acceptable, regular, and stable.", "keyphrases": ["cosmology", "f(r) gravity", "f(t) gravity", "f(t", "t) gravity", "gravitation", "modified gravity"]}
{"id": "poduval2023ai", "title": "AI-ready data in space science and solar physics: problems, mitigation and action plan", "abstract": "In the domain of space science, numerous ground-based and space-borne data of various phenomena have been accumulating rapidly, making analysis and scientific interpretation challenging. However, recent trends in the application of artificial intelligence (AI) have been shown to be promising in the extraction of information or knowledge discovery from these extensive data sets. Coincidentally, preparing these data for use as inputs to the AI algorithms, referred to as AI-readiness, is one of the outstanding challenges in leveraging AI in space science. Preparation of AI-ready data includes, among other aspects: 1) collection (accessing and downloading) of appropriate data representing the various physical parameters associated with the phenomena under study from different repositories; 2) addressing data formats such as conversion from one format to another, data gaps, quality flags and labeling; 3) standardizing metadata and keywords in accordance with NASA archive requirements or other defined standards; 4) processing of raw data such as data normalization, detrending, and data modeling; and 5) documentation of technical aspects such as processing steps, operational assumptions, uncertainties, and instrument profiles. Making all existing data AI-ready within a decade is impractical and data from future missions and investigations exacerbates this. This reveals the urgency to set the standards and start implementing them now. This article presents our perspective on the AI-readiness of space science data and mitigation strategies including definition of AI-readiness for AI applications; prioritization of data sets, storage, and accessibility; and identifying the responsible entity (agencies, private sector, or funded individuals) to undertake the task.", "keyphrases": ["ai-ready data", "decadal survey", "exoplanet", "machine learning", "planetary science", "space science", "space weather", "statistical methods"]}
{"id": "sibeck2023quantifying", "title": "Quantifying the global solar wind-magnetosphere interaction with the Solar-Terrestrial Observer for the Response of the Magnetosphere (STORM) mission concept", "abstract": "Much of what we know about the solar wind\u2019s interaction with the Earth\u2019s magnetosphere has been gained from isolated in-situ measurements by single or multiple spacecraft. Based on their observations, we know that reconnection, whether on the dayside magnetopause or deep within the Earth\u2019s magnetotail, controls the bulk flow of solar wind energy into and through the global system and that nightside activity provides the energized particles that power geomagnetic storms. But by their very nature these isolated in-situ measurements cannot provide an instantaneous global view of the entire system or its cross-scale dynamics. To fully quantify the dynamics of the coupled solar wind-magnetosphere requires comprehensive end-to-end global imaging of the key plasma structures that comprise the magnetosphere which have spatial resolutions that exceeds anything possible with multi-point or constellation situ measurements. Global, end-to-end, imaging provides the pathway to understanding the system as a whole, its constituent parts, and its cross-scale processes on a continuous basis, as needed to quantify the flow of solar wind energy through the global magnetospheric system. This paper describes how a comprehensively-instrumented single spacecraft in a high-altitude, high-inclination orbit coupled with ground-based instruments provides the essential observations needed to track and quantify the flow of solar wind energy through the magnetosphere. This includes observations of the solar wind plasma and magnetic field input, the magnetopause location in soft X-rays, the auroral oval in far ultraviolet, the ring current in energetic neutrals, the plasmasphere in extreme ultraviolet, the exosphere in Lyman-\u03b1, and the microstructure of the nightside auroral oval from ground-based all sky cameras.", "keyphrases": ["aurora", "global imaging", "mission concept", "plasma sphere", "ring current", "soft x rays", "solar wind-magnetosphere interaction"]}
{"id": "trinchera2023cosmological", "title": "Cosmological redshift and Hubble tension explained by means of the FLRWT time-metric framework and transit physics in the IGM", "abstract": "In response to all current cosmological controversies, this paper provides a reliable explanation of the Hubble tension and of the apparent acceleration of space expansion detected by SN Ia. In the first place, it calculates the redshift from Einstein field equations (EFE) assuming a Friedman\u2013Lemaitre\u2013Robertson\u2013Walker\u2013Trinchera (FLRWT) metric framework due to the deformation of the spacetime fabric, causing a redshift due to a time dilation. In the second place, this study computes the dominant cosmological redshift contribution given by the transit redshift due to multiple interactions between photons and electrons in the intergalactic medium and not sustained in Einstein field equations. It is fully consistent with Wigner\u2019s solid-state physics and Ashmore\u2019s physics which predict the crystallization of free electrons at very low temperatures and the interaction with photons of light without scattering and blurring effects. The outcome of this inquiry fully matches the observational data given by the redshift-independent extragalactic distances (NED-D) and by the Chandra/XMM-Newton database of quasars for a specific density of matter in the Universe.", "keyphrases": ["cosmological constant", "cosmological redshift", "intergalactic medium", "solid-state physics", "spacetime curvature", "time dilation"]}
{"id": "lavraud2023what", "title": "What is the heliopause? Importance of magnetic reconnection and measurement requirements", "abstract": "We highlight the importance of magnetic reconnection at the heliopause, both as one of the key processes driving the interaction between solar and interstellar media, but also as an element of the definition of the heliopause itself. We highlight the main observations that have fed the current debates on the definition, location and shape of the heliopause. We explain that discriminating between the current interpretations of plasma and magnetic field structures near the heliopause necessitates appropriate measurements which are lacking on Voyager 1 and 2, and describe some of the ensuing requirements for thermal plasma measurements on a future Interstellar Probe. The content of this article was submitted as a white paper contribution to the Decadal Survey for Solar and Space Physics 2024\u20132033 of the National Academy of Sciences.", "keyphrases": ["heliopause", "heliosheath", "heliosphere", "instrumentation", "interstellar medium", "magnetic reconnection", "solar wind"]}
{"id": "javed2023thermal", "title": "Thermal fluctuations, QNMs, and emission energy of charged ADS black hole with nonlinear electrodynamics", "abstract": "This study examines the thermodynamics of charged anti-de Sitter (AdS) black holes (BHs) with nonlinear electrodynamics (NED) using quasinormal modes (QNMs) and thermal fluctuations. For this purpose, we calculate the Hawking temperature and discuss the stable configuration of the considered black hole using heat capacity. First, we study the interesting aspects of the emission of energy. Then, we explore the effects of thermal corrections on thermodynamic quantities and their corrected energies. We study the phase transitions of the system in the background of thermal fluctuations. It is concluded that the presence of a coupling constant enhances the thermodynamically stable configuration of uncharged and charged AdS BH geometries. We highlight that our results are in good agreement with the thermodynamics of the previous black hole solutions and assumptions presented in the literature.", "keyphrases": ["nonlinear electrodynamics", "null geodesics", "phase transitions", "quasinormal modes", "thermal fluctuations", "thermodynamics"]}
{"id": "maetschke2023possible", "title": "A possible mechanism for the formation of an eastward moving auroral spiral", "abstract": "The generation process of auroral spirals is described by different theories varying for their morphology and surrounding conditions. Here, a possible mechanism is proposed for an eastward moving auroral spiral, which was observed in Troms\u00f8, Norway, during the expansion phase of a substorm on 18 September 2013. Measurements from the THEMIS-A and Cluster spacecraft were analyzed, which were located up to \u223c10 RE duskward from the spiral generator region in the magnetosphere. Precursory to the spiral observation, concurrent magnetic field dipolarizations, flow bursts and electron injections were measured by the Cluster satellites between 13.6 and 14.2 RE radial distance from Earth. A local Kelvin-Helmholtz-like vortex street in the magnetic field was detected at the same time, which was likely caused by bursty bulk flows. The vortex street was oriented approximately in the X-Y (GSE) plane and presumably propagated towards the source region of the spiral due to a high dawnward velocity component in the flow bursts. The observations suggest that the spiral can have been generated by an associated vortex in the magnetotail and then mapped along the magnetic field lines to the ionosphere. To better understand the role of the ionosphere in auroral spiral generation, in future more mesoscale observations are required.", "keyphrases": ["aurora", "auroral spiral", "bursty bulk flows", "kelvin-helmholtz instability", "substorm"]}
{"id": "jiao2023dense", "title": "Dense gas star formation efficiency and the (Formula presented.) ratio: insights from a statistical study of infrared bright star-forming galaxies", "abstract": "We present a statistical study on dense molecular gas tracers of HCN (4\u20133), HCO+ (4\u20133) lines and molecular tracers of [C i], and CO observations for a sample of 26 infrared bright star-forming (SF) galaxies. We investigate the dependence of dense gas star formation efficiency traced by HCN (4\u20133), HCO+ (4\u20133) (that is (Formula presented.), and (Formula presented.)), and luminosity ratio of (Formula presented.) on [C i]-CO ratios of (Formula presented.), (Formula presented.) and (Formula presented.) (hereafter R[CI]) which are sensitive to interstellar medium conditions. Our findings show that both (Formula presented.) and (Formula presented.) have moderate correlations with (Formula presented.) and R[CI], while (Formula presented.) does not show any significant correlations with any of the [C i]-CO ratios. We compare the (Formula presented.) ratios of AGN and SF galaxies, and find that although the higher (Formula presented.) ratios are mainly found in AGN, the majority of the (Formula presented.) values in SF galaxies are comparable to those in AGN. Based on our findings, it appears that the (Formula presented.) ratio may not be a reliable indicator of the presence of an AGN, although further investigation is needed to confirm this conclusion.", "keyphrases": ["agn -active galactic nucleus", "dense molecular gas", "hcn (4\u22123)", "hco + (4\u22123)", "sample", "star formation-galaxies"]}
{"id": "ganguly2023nature", "title": "The nature of the motions of multiphase filaments in the centers of galaxy clusters", "abstract": "The intracluster medium (ICM) in the centers of galaxy clusters is heavily influenced by the \u201cfeedback\u201d from supermassive black holes (SMBHs). Feedback can drive turbulence in the ICM and turbulent dissipation can potentially be an important source of heating. Due to the limited spatial and spectral resolutions of X-ray telescopes, direct observations of turbulence in the hot ICM have been challenging. Recently, we developed a new method to measure turbulence in the ICM using multiphase filaments as tracers. These filaments are ubiquitous in cluster centers and can be observed at very high resolution using optical and radio telescopes. We study the kinematics of the filaments by measuring their velocity structure functions (VSFs) over a wide range of scales in the centers of (Formula presented.) galaxy clusters. We find features of the VSFs that correlate with the SMBHs activities, suggesting that SMBHs are the main driver of gas motions in the centers of galaxy clusters. In all systems, the VSF is steeper than the classical Kolmogorov expectation and the slopes vary from system to system. One theoretical explanation is that the VSFs we have measured so far mostly reflect the motion of the driver (jets and bubbles) rather than the cascade of turbulence. We show that in Abell 1795, the VSF of the outer filaments far from the SMBH flattens on small scales to a Kolmogorov slope, suggesting that the cascade is only detectable farther out with the current telescope resolution. The level of turbulent heating computed at small scales is typically an order of magnitude lower than that estimated at the driving scale. Even though SMBH feedback heavily influences the kinematics of the ICM in cluster centers, the level of turbulence it drives is rather low, and turbulent heating can only offset \u2272 10", "keyphrases": ["active galactic nuclei", "galaxy clusters", "galaxy physics", "intracluster medium", "turbulence", "x-ray cavities"]}
{"id": "wang2023ability", "title": "The ability of CSST to determine the orbital solutions of SB1s", "abstract": "The single-lined spectroscopic binaries (SB1s) are composed of two components with large difference in masses and in physical properties. The orbital and physical parameters of a large number of such binary systems are unknown due to lack of necessary observations. Compared with SB2s, SB1s can provide much more stringent constraint to stellar evolutionary models at a single age. Besides, the fainter components of SB1s are likely to be compact celestial objects, such as a black hole or a neutron star, it is therefore interesting to determine their masses and physical properties. CSST provides an excellent opportunity to study SB1s especially nearby ones, since it can detect astrometric wobble at milliarcsecond level. This implies that if the motion of the visible components can be detected, the full motion of the SB1s can be determined. In this paper, we aim to analyse the ability of CSST to improve the orbital solutions of nearby SB1s based on the available data by adding simulated CSST data of different observation times. The orbital solutions of binaries determined from non-single-star orbital models for sources compatible with combined astrometric + single lined spectroscopic orbital model of Gaia DR3 are served as the research sample to reproduce the orbital elements by fitting simulated CSST data.", "keyphrases": ["binary", "csst", "numerical simulation", "orbital solution", "sb1"]}
{"id": "landt2023outer", "title": "The outer dusty edge of accretion disks in active galactic nuclei", "abstract": "Recent models for the inner structure of active galactic nuclei (AGN) aim at connecting the outer region of the accretion disk with the broad-line region and dusty torus through a radiatively accelerated, dusty outflow. Such an outflow not only requires the outer disk to be dusty and thus predicts disk sizes beyond the self-gravity limit but requires the presence of nuclear dust with favorable properties. Here, we investigate a large sample of type 1 AGN by near-infrared (near-IR) cross-dispersed spectroscopy with the aim to constrain the astrochemistry, location, and geometry of the nuclear hot dust region. Assuming a thermal equilibrium for optically thin dust, we derive the luminosity-based dust radius for different grain properties using our measurement of the temperature. We combine our results with independent dust radius measurements from reverberation mapping and interferometry, and show that large dust grains that can provide the necessary opacity for the outflow are ubiquitous in AGN. Using our estimates of the dust covering factor, we investigate the dust geometry using the effects of the accretion disk anisotropy. A flared disk-like structure for the hot dust is favored. Finally, we discuss the implication of our results for the dust radius-luminosity plane.", "keyphrases": ["active galactic nuclei", "dust continuum emission", "dust physics", "near-infrared astronomy", "quasars"]}
{"id": "lake2023dimensionally", "title": "Dimensionally-dependent uncertainty relations, or why we (probably) won\u2019t see micro-black holes at the LHC, even if large extra dimensions exist", "abstract": "We present a simple gedanken experiment in which a compact object traverses a spacetime with three macroscopic spatial dimensions and n compact dimensions. The compactification radius is allowed to vary, as a function of the object\u2019s position in the four-dimensional space, and we show that the conservation of gravitational self-energy implies the dimensional dependence of the mass-radius relation. In spacetimes with extra dimensions that are compactified at the Planck scale, no deviation from the four-dimensional result is found, but, in spacetimes with extra dimensions that are much larger than the Planck length, energy conservation implies a deviation from the normal Compton wavelength formula. The new relation restores the symmetry between the Compton wavelength and Schwarzschild radius lines on the mass-radius diagram and precludes the formation of black holes at TeV scales, even if large extra dimensions exist. We show how this follows, intuitively, as a direct consequence of the increased gravitational field strength at distances below the compactification scale. Combining these results with the heuristic identification between the Compton wavelength and the minimum value of the position uncertainty, due to the Heisenberg uncertainty principle, suggests the existence of generalised, higher-dimensional uncertainty relations. These relations may be expected to hold for self-gravitating quantum wave packets, in higher-dimensional spacetimes, with interesting implications for particle physics and cosmology in extra-dimensional scenarios.", "keyphrases": ["compactification", "compton wavelength", "generalised uncertainty relations contents", "higher dimensions", "primordial black holes", "self-gravity"]}
{"id": "bl\u00e1zquez_salcedo2022\u03d5", "title": "\u03d5-modes of neutron stars in a massless scalar\u2013tensor theory", "abstract": "Scalar\u2013tensor theories allow for a rich spectrum of quasinormal modes of neutron stars. The presence of the scalar field allows for polar monopole and dipole radiation, as well as for additional higher multipole modes led by the scalar field. Herein, we present one family of the modes which are dominated by the scalar fields, the scalar-led \u03d5-modes computed numerically with a shooting method, for the lowest multipoles, that is, l = 0, 1, and 2 for a massless scalar\u2013tensor theory of the Brans\u2013Dicke type, motivated by the (Formula presented.) theory, and compare with those of a minimally coupled scalar field in general relativity. We consider a set of six realistic equations of state and extract universal relations for the modes.", "keyphrases": ["equation of state", "gravitational waves", "neutron stars", "quasinormal modes", "scalar\u2013tensor theory", "universal relations"]}
{"id": "tsikata2022incoherent", "title": "Incoherent Thomson scattering: future implementation and measurement capabilities on the PANDORA experiment", "abstract": "The PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) experiment aims to study the \u03b2-decay process inside a dense plasma mimicking stellar conditions. An electron cyclotron resonance plasma trap will be built at INFN-LNS in Catania, Italy, for the generation of the desired conditions in the laboratory. This type of non-equilibrium dense plasma (reaching densities of up to 1013 cm\u22123) is expected to generate electron energy distribution functions with electron energies ranging from tens of eV up to tens of keV. In this work, we describe aspects of a planned implementation of an incoherent Thomson scattering diagnostic for the study of electron properties in the plasma trap of PANDORA. The performance of this high-sensitivity diagnostic, known as THETIS, has been previously validated in measurements across a range of low-density magnetized plasma environments and it is expected to provide access to electron energy information in PANDORA in the range of temperatures from 1 to 103 eV. This article will establish the potential of such a diagnostic for future characterization of the electron properties in the PANDORA experiment.", "keyphrases": ["electron cyclotron resonance (ecr)", "electron density", "electron temperature", "incoherent thomson scattering", "laser diagnostics", "magnetic trap", "stellar plasmas"]}
{"id": "pidatella2022experimental", "title": "Experimental and numerical investigation of magneto-plasma optical properties toward measurements of opacity relevant for compact binary objects", "abstract": "Electromagnetic transients known as kilonovae (KN), are among the photonic messengers released in the post-merger phase of compact binary objects, for example, binary neutron stars, and they have been recently observed as the electromagnetic counterpart of related gravitational-wave (GW) events. Detection of the KN signal plays a fundamental role in the multi-messenger astronomy entering in a sophisticated GW-detecting network. The KN light curve also delivers precious information on the composition and dynamics of the neutron-rich post-merger plasma ejecta (relying on r-process nucleosynthesis yields). In this sense, studying KN becomes of great relevance for nuclear astrophysics. Because of the highly heterogeneous composition, plasma opacity has a great impact both on radiative transport and spectroscopic observation of KN. Theoretical models attempting in encoding the opacity of this system often fail, due to the complexity of blending plethora of both light- and heavy-r nuclei transition lines, requesting for more complete atomic database. Trapped magneto-plasmas conceived in PANDORA could answer to these requests, allowing experimental in-laboratory measurements of optical properties and opacities, at plasma electron densities and temperatures resembling early-stage plasma ejecta\u2019s conditions, contributing to shed light on r-process metallic species abundance at the blue-KN diffusion time. A numerical study has been recently performed, supporting the choice of first physics cases to be investigated and the design of the experimental setup. In this article, we report on the feasibility of metallic plasmas on the basis of the results from the systematic numerical survey on optical spectra computed under non-local thermodynamic equilibrium (NLTE) for several light-r nuclei. Results show the great impact of the NLTE regime of laboratory magneto-plasmas on the gray opacity contribution contrasted with those under the astrophysical LTE assumption. A first experimental attempt of reproducing ejecta plasma conditions has been performed on the operative Flexible Plasma Trap (FPT) at the INFN-LNS and here presented, together with first plasma characterization of density and temperature, via non-invasive optical emission spectroscopy (OES). The measured plasma parameters have supported numerical simulations to explore optical properties of NLTE gaseous and metallic plasmas, in view of the near-future plasma opacity measurements through spectroscopic techniques. The novel work so far performed on these under-dense and low-temperature magneto-plasmas, opens the route for the first-time to future in-laboratory plasma opacity measurements of metallic plasma species relevant for KN light curve studies.", "keyphrases": ["kilonovae", "multi-messenger astronomy", "nuclear astrophysics", "plasma physics", "plasma spectroscopy"]}
{"id": "wimmer_schweingruber2022stella", "title": "STELLA\u2014Potential European contributions to a NASA-led interstellar probe", "abstract": "The discovery of a myriad of exoplanets in the past decades has revolutionized the understanding of our place in the Universe. How different are exoplants and do some of them harbor life, just like Earth? To do so, their parent stars must drive a stellar wind and carve what we call astrospheres into the surrounding interstellar medium. Astrospheres are ubiquitous in our immediate neighborhood and show similar structure to our heliosphere. Voyager 1 and 2, Ulysses, Cassini, and IBEX have shown that the interaction between interstellar medium and solar wind is much more complex and involved than previously believed. This stellar-interstellar interaction is key to understand astrospheres and the shielding they provide to the planetary systems they harbor. This article summarizes a whitepaper that was submitted to NASA\u2019s 2023/2024 decadal survey which is being conducted by the US National Academies. It is based in parts on a proposal submitted to the European Space Agency (ESA) in response to its 2021 call for medium-class mission proposals. The whitepaper and this article propose to study the interaction described above in situ at the heliospheric boundaries and to explore the very local interstellar medium beyond. Furthermore, they highlight possible European contributions to a NASA-led Interstellar Probe (ISP).", "keyphrases": ["fundamental physics", "interstellar probe", "mission proposal", "solar system", "space science", "very local interstellar medium"]}
{"id": "beattie2022ion", "title": "Ion alfv\u00e9n velocity fluctuations and implications for the diffusion of streaming cosmic rays", "abstract": "The interstellar medium (ISM) of star-forming galaxies is magnetized and turbulent. Cosmic rays (CRs) propagate through it, and those with energies from \u223c GeV \u2212 TeV are likely subject to the streaming instability, whereby the wave damping processes balances excitation of resonant ionic Alfv\u00e9n waves by the CRs, reaching an equilibrium in which the propagation speed of the CRs is very close to the local ion Alfv\u00e9n velocity. The transport of streaming CRs is therefore sensitive to ionic Alfv\u00e9n velocity fluctuations. In this paper we systematically study these fluctuations using a large ensemble of compressible MHD turbulence simulations. We show that for sub-Alfv\u00e9nic turbulence, as applies for a strongly magnetized ISM, the ionic Alfv\u00e9n velocity probability density function (PDF) is determined solely by the density fluctuations from shocked gas forming parallel to the magnetic field, and we develop analytical models for the ionic Alfv\u00e9n velocity PDF up to second moments. For super-Alfv\u00e9nic turbulence, magnetic and density fluctuations are correlated in complex ways, and these correlations as well as contributions from the magnetic fluctuations sets the ionic Alfv\u00e9n velocity PDF. We discuss the implications of these findings for underlying \u201cmacroscopic\u201d diffusion mechanisms in CRs undergoing the streaming instability, including modeling the macroscopic diffusion coefficient for the parallel transport in sub-Alfv\u00e9nic plasmas. We also describe how, for highly-magnetized turbulent gas, the gas density PDF, and hence column density PDF, can be used to access information about ionic Alfv\u00e9n velocity structure from observations of the magnetized ISM.", "keyphrases": ["cosmic rays", "galaxies", "magnetic fields", "magnetohydrodynamic turbulence", "multi-phase interstellar medium"]}
{"id": "carson2022dlite", "title": "DLITE\u2014An inexpensive, deployable interferometer for solar radio burst observations", "abstract": "Solar radio bursts (SRBs) are brief periods of enhanced radio emission from the Sun. SRBs can provide unique insights into the plasma structure where emission occurs. SRBs can also provide critical information concerning space weather events such as coronal mass ejections or solar energetic particle events. Providing continuous monitoring of SRBs requires a full network of detectors continuously monitoring the Sun. A promising new network is being developed, employing a four-element interferometer called the Deployable Low-band Ionosphere and Transient Experiment (DLITE) array. DLITE, which operates in a 30\u201340 MHz band, was specifically designed to probe the Earth\u2019s ionosphere using high resolution measurements (1.024-s temporal resolution, 16.276-kHz frequency resolution); however, this also makes DLITE a powerful new tool for providing detailed observations of SRBs at these frequencies. DLITE is particularly adept at detecting long-duration SRBs like Type II and Type IV bursts. DLITE provides high resolution SRB data that can complement ground-based networks like e-Callisto or space-based observations, e.g., from Wind/WAVES. As an inexpensive interferometer, DLITE has strong potential as an educational tool: DLITE can be used to study the ionosphere, SRBs, and even Jovian radio bursts. Future DLITE arrays could be enhanced by using the full 20\u201380 MHz band accessible by the antennas and employing its millisecond time-resolution capability; this would improve DLITE\u2019s ability to track long-duration bursts, create the opportunity to study short-duration Type III bursts in detail, and, in particular, make the study of Type I bursts practical.", "keyphrases": ["coronal mass ejection", "coronal plasma density", "radio astronomy", "solar corona", "solar radio bursts"]}
{"id": "busso2022production", "title": "Production of solar abundances for nuclei beyond Sr: The s- and r-process perspectives", "abstract": "We present the status of nucleosynthesis beyond Sr, using up-to-date nuclear inputs for both the slow (s-process) and rapid (r-process) scenarios of neutron captures. It is now widely accepted that at least a crucial part of the r-process distribution is linked to neutron star merger (NSM) events. However, so far, we have found only a single direct observation of such a link, the kilonova GW170817. Its fast evolution could not provide strict constraints on the nucleosynthesis details, and in any case, there remain uncertainties in the local r-process abundance patterns, which are independent of the specific astrophysical site, being rooted in nuclear physics. We, therefore, estimate the contributions from the r-process to solar system (S.S.) abundances by adopting the largely site-independent waiting-point concept through a superposition of neutron density components normalized to the r-abundance peaks. Nuclear physics inputs for such calculations are understood only for the trans-Fe nuclei; hence, we restrict our computations to the Sr\u2013Pr region. We then estimate the s-process contributions to that atomic mass range from recent models of asymptotic giant branch stars, for which uncertainties are known to be dominated by nuclear effects. The outcomes from the two independent approaches are then critically analyzed. Despite the remaining problems from both sides, they reveal a surprisingly good agreement, with limited local discrepancies. These few cases are then discussed. New measurements in ionized plasmas are suggested as a source of improvement, with emphasis on \u03b2-decays from unstable Cs isotopes. For heavier nuclei, difficulties grow as r-process progenitors lie far off experimental reach and poorly known branchings affect s-processing. This primarily concerns nuclei that are significantly long-lived in the laboratory and have uncertain decay rates in stars, e.g., (Formula presented.) and (Formula presented.). New measurements are urgently needed for them, too.", "keyphrases": ["nuclear astrophysics", "nucleosynthesis", "s-processes", "r-processes", "stars", "weak interactions"]}
{"id": "su\u00e1rez2022potential", "title": "The potential of Shannon entropy to find the large separation of \u03b4 Scuti stars: The entropy spectrum", "abstract": "This study explores the use of Shannon entropy to find periodic patterns in the oscillation spectra of \u03b4 Scuti stars. We have developed a new diagnostic tool for detecting potential patterns that scans for minimal entropic states in the well-known \u00e9chelle diagrams. Here, we describe the basic mathematical grounds of the Shannon entropy and how it can be applied to \u00e9chelle diagrams through a new diagnostic diagram: the entropy (H) spectrum (HSpec). The method is first validated with the solar-like pulsator HD 49933, for which the large separation was found compatible with values published in the literature. Then we computed the entropy spectrum for two well-studied \u03b4 Scuti stars: HD 174936 and HD 174966, for which HSpec analysis was able to accurately determine their large separation (or some multiple or submultiple of it). Although these results are promising, the HSpec tool presents several limitations: it has a strong dependence on the probability distribution of the frequencies in the \u00e9chelle diagram, and on the way it is calculated. We discuss possible solutions to this that rely on 2D probability distributions and conditional entropy.", "keyphrases": ["asteroseismology", "delta scuti stars", "information theory", "solar-like oscillations", "stellar pulsations", "stellar structure and evolution", "time series analysis"]}
{"id": "ledvina2022how", "title": "How open data and interdisciplinary collaboration improve our understanding of space weather: A risk and resiliency perspective", "abstract": "Space weather refers to conditions around a star, like our Sun, and its interplanetary space that may affect space- and ground-based assets as well as human life. Space weather can manifest as many different phenomena, often simultaneously, and can create complex and sometimes dangerous conditions. The study of space weather is inherently trans-disciplinary, including subfields of solar, magnetospheric, ionospheric, and atmospheric research communities, but benefiting from collaborations with policymakers, industry, astrophysics, software engineering, and many more. Effective communication is required between scientists, the end-user community, and government organizations to ensure that we are prepared for any adverse space weather effects. With the rapid growth of the field in recent years, the upcoming Solar Cycle 25 maximum, and the evolution of research-ready technologies, we believe that space weather deserves a reexamination in terms of a \u201crisk and resiliency\u201d framework. By utilizing open data science, cross-disciplinary collaborations, information systems, and citizen science, we can forge stronger partnerships between science and industry and improve our readiness as a society to mitigate space weather impacts. The objective of this manuscript is to raise awareness of these concepts as we approach a solar maximum that coincides with an increasingly technology-dependent society, and introduce a unique way of approaching space weather through the lens of a risk and resiliency framework that can be used to further assess areas of improvement in the field.", "keyphrases": ["geospace", "open data", "open science", "risk and resiliency", "solar activity", "solar storms", "space weather", "sun and society"]}
{"id": "nikulin2022compact", "title": "Compact extra dimensions as the source of primordial black holes", "abstract": "This article discusses a model of primordial black hole (PBH) formation at the reheating stage. These small/massive black holes appear due to the specific properties of the compact extra dimensions. The latter gives rise to the low energy model, containing an effective scalar field potential capable of domain wall production. Formed during inflation, these walls are quite dense, meaning they collapse soon after inflation ends. Discussion of the model is framed by the scope of multidimensional f(R)-gravity. We study the possibility of the pure gravitational formation of primordial black holes (PBHs). Interpreting the scalar curvature of compact extra space Rn as an effective scalar field in an Einstein framework and consider effective scalar-field theory that might potentially be capable of producing domain walls with a certain choice of parameters. Hence, we demonstrate that f(R)-gravity contains a mechanism for PBH formation. The study assumed that cosmological inflation is an external process, which satisfied all the cosmological constraints on our mechanism.", "keyphrases": ["cosmology", "domain wall", "extra dimensions", "f(r)-gravity", "gravity", "modified gravity", "primordial black holes"]}
{"id": "batra2022missing", "title": "The missing conformer: A comprehensive rotational spectroscopy study and astronomical search of two conformers of methyl cyanoacetate", "abstract": "We performed a comprehensive investigation of methyl cyanoacetate (MCA) using high-resolution Fourier transform rotational spectroscopy. Two low energy conformers of MCA were observed in the vibrational ground state, in selected frequency regions from 2 to 110 GHz. We report accurately determined line lists, rotational constants, centrifugal distortion constants, and nuclear quadrupole coupling constants for both conformers, as well as for several singly substituted heavy-atom isotopologues. One of the conformers was previously reported; however, the rotational transitions of the second conformer, which is newly described here, are observed to be generally more intense than the latter. The accurate predictions of rotational transitions into the millimeter-wave region can facilitate the detection of these conformers of MCA in the interstellar medium. Using the rotational spectroscopy data provided here, we searched for the two conformers of MCA in a deep and unbiased spectral survey of the molecular cloud G+0.693-0.027 located in the Galactic Center. None of the MCA conformers were detected. The upper limits for their abundances were derived with respect to the abundance of molecular hydrogen.", "keyphrases": ["astrochemistry", "interstellar medium", "methyl cyanoacetate", "molecular structure", "rotational spectroscopy"]}
{"id": "tourgaidis2022wave", "title": "Wave-particle interactions toolset: A python-based toolset to model wave-particle interactions in the magnetosphere", "abstract": "Wave particle interactions are known to be an efficient yet unquantified driver of the variability of particle populations in Earth\u2019s magnetosphere, and their quantification and understanding through modelling has been a subject of ceaseless and extensive research during the last decades. Moreover, there is an increasing interest in techniques for radiation belt remediation, which refers to artificially controlling energetic particle populations in the near-Earth space environment via the scattering of particles from artificially generated electromagnetic waves. Whereas numerous modelling techniques are described in literature, there is a lack of a unified open-source toolset that incorporates the equations and parameterizations used by different wave-particle interaction models in a user-friendly environment. We present WPIT, the Wave-Particle Interactions Toolset, an open source, Python-based set of tools for modelling the interactions between energetic charged particles and VLF waves in the magnetosphere through test particle simulations. WPIT incorporates key routines related to wave-particle interactions in Python modules and also in Jupyter Notebook environment, enabling the traceability of all relevant equations in terms of their derivation and key assumptions, together with the programming environment and integrated graphics that enable users to conduct state-of-the-art wave-particle interaction simulations rapidly and efficiently. WPIT can be used either as a stand-alone simulation tool or as a library of routines that the user can extract and incorporate into an independent simulation. We present an analytic description of the code, the methodology used, and examples based on each of the WPIT modules. WPIT examples include the exact reproduction of simulation results that have been reported in literature, based on the same sets of parameters and assumptions, allowing the user to expand upon state-of-the-art. Finally, using the WPIT toolset, we perform a parametric analysis on the onset of nonlinear interactions between electrons with whistler-mode waves by varying the relevant parameters of the waves (amplitude, wave normal angle and frequency), the particles (pitch angle and energy) and the plasma environment (electron density and ion composition).", "keyphrases": ["emic", "magnetosphere", "nonlinear interactions", "python for space physics", "vlf waves", "wave-particle interactions toolset", "whistler", "wpit"]}
{"id": "heitk\u00e4mper2022reactivity", "title": "The reactivity of pyridine in cold interstellar environments: The reaction of pyridine with the CN radical", "abstract": "The recent detection of cyclic species in cold interstellar environments is an exciting discovery with yet many unknowns to be solved. Among them, the presence of aromatic heterocycles in space would act as an indirect evidence of the presence of precursors of nucleotides. The seeming absence of these species in the observations poses a fascinating conundrum that can be tackled with computational insights. Whilst many arguments can be given to explain the absence of heterocycles in space, one of the possible scenarios involves fast chemical conversion and formation of new species to be detected. We have tested this hypothesis for the reaction of pyridine with the CN radical to find possible scenarios in which the detectability of pyridine, as an archetypical heterocycle, could be enhanced or diminished via chemical conversions. Using a combination of ab-initio characterization of the reactive potential energy surface and kinetic and chemical simulations, we have established that pyridine does react very fast with CN radicals, estimating that the studied reactions is between 2.5\u20134.5 times faster in pyridine than in benzene, with a total loss rate constant of 1.33 \u00d7 10\u20139 cm3s\u22121 at 30 K, with an almost null temperature dependence in the (30\u2013150) K range. Addition reactions forming 1,2,3-cyanopyridine are favored over abstraction reactions or the formation of isocyanides. Besides, for 1 and 2-cyanopyridine there is an increase in the total dipole moment with respect to pyridine, which can help in their detection. However, the reaction is not site specific, and equal amounts of 1,2,3-cyanopyridine are formed during the reaction, diluting the abundance of all the individual pyridine derivatives.", "keyphrases": ["astrochemistry", "computational methods", "heterocycles", "interstellar medium", "proxy species"]}
{"id": "palmroos2022solar", "title": "Solar energetic particle time series analysis with Python", "abstract": "Solar Energetic Particles (SEPs) are charged particles accelerated within the solar atmosphere or the interplanetary space by explosive phenomena such as solar flares or Coronal Mass Ejections (CMEs). Once injected into the interplanetary space, they can propagate towards Earth, causing space weather related phenomena. For their analysis, interplanetary in situ measurements of charged particles are key. The recently expanded spacecraft fleet in the heliosphere not only provides much-needed additional vantage points, but also increases the variety of missions and instruments for which data loading and processing tools are needed. This manuscript introduces a series of Python functions that will enable the scientific community to download, load, and visualize charged particle measurements of the current space missions that are especially relevant to particle research as time series or dynamic spectra. In addition, further analytical functionality is provided that allows the determination of SEP onset times as well as their inferred injection times. The full workflow, which is intended to be run within Jupyter Notebooks and can also be approachable for Python laymen, will be presented with scientific examples. All functions are written in Python, with the source code publicly available at GitHub under a permissive license. Where appropriate, available Python libraries are used, and their application is described.", "keyphrases": ["coronal mass ejection (cme)", "data", "heliosphere", "onset time", "python", "software package", "solar energetic particle (sep)", "spacecraft"]}
{"id": "sehring2022spectral", "title": "The spectral features and detectability of small, cyclic silicon carbide clusters", "abstract": "Rovibrational spectral data for several tetra-atomic silicon carbide clusters (TASCCs) are computed in this work using a CCSD(T)-F12b/cc-pCVTZ-F12 quartic force field. Accurate theoretical spectroscopic data may facilitate the observation of TASCCs in the interstellar medium which may lead to a more complete understanding of how the smallest silicon carbide (SiC) solids are formed. Such processes are essential for understanding SiC dust grain formation. Due to SiC dust prevalence in the interstellar medium, this may also shed light on subsequent planetary formation. Rhomboidal Si2C2 is shown here to have a notably intense (247 km mol\u22121) anharmonic vibrational frequency at 988.1 cm\u22121 (10.1 \u03bcm) for \u03bd2, falling into one of the spectral emission features typically associated with unknown infrared bands of various astronomical regions. Notable intensities are also present for several of the computed anharmonic vibrational frequencies including the cyclic forms of C4, SiC3, Si3C, and Si4. These features in the 6\u201310 \u03bcm range are natural targets for infrared observation with the James Webb Space Telescope (JWST)\u2019s MIRI instrument. Additionally, t-Si2C2, d-Si3C, and r-SiC3 each possess dipole moments of greater than 2.0 D making them interesting targets for radioastronomical searches especially since d-SiC3 is already known in astrophysical media.", "keyphrases": ["astrochemistry", "carbon chemistry", "coupled cluster theory", "infrared observations", "silicon chemistry", "vibrational spectroscopy"]}
{"id": "mathew2022methanol", "title": "Methanol in the RNA world: An astrochemical perspective", "abstract": "The role and relevance of methanol in the origin and structure of the RNA world is discussed. Methanol is a pivotal, renewable, and regenerable source from which almost all chemical materials, simple or complex, can be accessed. Olefins and carbonyl compounds, amines and amino acids, peptides and polypeptides, and the molecular building blocks in the initial stages of the biological evolution to life\u2019s origin are obtained through methanol as a source material by its chemical transformation. The formation of methanol, whether in stellar and interstellar media, in deep sea-bottom hot hydrothermal vents or from geothermal sources, results from CO2 hydrogenation. It is the basic reaction, setting the stage for the formation of fundamental \u201corganic\u201d building blocks for the formation of simple prebiotic cells to subsequent biological evolution to cells. The important observation of many organics\u2013 hydrocarbons and ions including the large expanse of methane and methanol in the interstellar medium and stellar peripheries is a clear indication of \u201cstellar reductive processes\u201d and ensuing reactions shedding light on the probable significant role of extraterrestrial methanol as the basic source material toward a multi-step transformation into complex life molecules such as RNA.", "keyphrases": ["astro methanol-to-olefin (amto) synthesis", "carbonaceous meteorites", "complex organic molecules (coms)", "interstellar medium (ism)", "quantum mechanical tunneling", "the methanol economy"]}
{"id": "dinerstein2022observing", "title": "Observing the signatures of AGB s-process nucleosynthesis in planetary nebulae: An origins story", "abstract": "I relate an anecdotal history of the beginnings of a new initiative in studies of the chemical composition of planetary nebulae: namely, investigating abundances of elements beyond the iron-peak through infrared spectroscopy. In some planetary nebulae many of these elements display enrichments due to neutron capture reactions within the progenitor stars. This snippet of history provides an example of how science advances from the convergence of improvements in instrumentation, cross-over between fields, and constructive interaction between theory and observation. It also highlights the fact that terra incognita and discovery space remains even in seemingly well-established fields of science.", "keyphrases": ["asymptotic giant branch (agb) stars", "chemical abundances", "infrared spectroscopy", "nucleosynthesis", "planetary nebulae", "s-process", "stellar evolution"]}
{"id": "komm2022radial", "title": "Radial gradient of the solar rotation rate in the near-surface shear layer of the Sun", "abstract": "We study the radial gradient of the solar rotation rate in the near-surface shear layer (NSSL) from about.950 R\u2299 to the solar surface and its variation during Solar Cycles 23 and 24 with ring-diagram analysis applied to Global Oscillation Network Group (GONG) and Helioseismic and Magnetic Imager (HMI) Dopplergrams. The average radial gradient is \u2202 log \u03a9/\u2202 log r = \u2212 1.0 \u00b1.1 at.990 R\u2299 in agreement with previous studies. The average radial gradient is \u2202 log \u03a9/\u2202 log r = \u2212.11 \u00b1.01 at the base of the NSSL at.950R\u2299, while it is steeper than \u22121 closer to the surface between.990R\u2299 and.997R\u2299. The average radial gradient is rather flat within \u00b140\u00b0 latitude from about.970 R\u2299 to the solar surface. The radial gradient of the solar rotation rate varies with the solar cycle. At locations of high magnetic activity, the radial gradient is more negative than average from about.970 R\u2299 to.990 R\u2299, while in quiet regions the radial gradient is less negative than average at these depths. Close to the surface at.997 R\u2299, this relationship appears to be reversed. Prominent features of the solar-cycle variation of large-scale flows, such as poleward branches or precursor flows, are not obviously present. The variation of the radial gradient thus more likely indicates the presence or absence of magnetic flux above a certain threshold. The temporal variations derived from the different HMI and GONG data sets agree within one error bar at most depths and latitudes, while their amplitudes might be different.", "keyphrases": ["helioseismology", "observations", "solar cycle", "solar interior", "solar rotation", "the sun", "velocity fields"]}
{"id": "lekshmi2022sub", "title": "Sub-surface plasma flows and the flare productivity of solar active regions", "abstract": "The extreme space weather conditions resulting from high energetic events likes solar flares and Coronal Mass Ejections demand for reliable space weather forecasting. The magnetic flux tubes while rising through the convection zone gets twisted by the turbulent plasma flows, energizing the system and resulting in flares. We investigate the relationship between the subsurface plasma flows associated with flaring active regions and their surface magnetic flux and current helicity. The near-surface horizontal velocities derived from the ring-diagram analysis of active region patches using Global Oscillation Network Group Doppler velocity measurements are used to compute the fluid dynamics descriptors like vertical divergence, vorticity and kinetic helicity used in this work. The flaring active regions are observed to have large value of vertical vorticity and kinetic helicity. Also, the horizontal flow divergence, vorticity, flux, kinetic and current helicities are observed to be significantly correlated and evolve in phase with each other. We observe that the integrated values of the above flow and magnetic parameters observed 1 day prior to the flare are significantly correlated with the integrated flare intensity of the active region. Hence, we show that strong vorticity/kinetic helicities lead to larger active region twisting, presumably generating high-intensity flares.", "keyphrases": ["active regions", "flares", "helicity", "helioseismology", "plasma flows", "sun"]}
{"id": "niu2022quantitative", "title": "Quantitative study of the hardening in the Alpha Magnetic Spectrometer nuclei spectra at a few hundred GV", "abstract": "The most significant feature in the cosmic-ray (CR) nuclei spectra is the spectral hardening at a few hundred GV. It is important to know whether the hardening of different nuclei species is the same or not for constructing CR sources and propagation models. In this work, we collect the recently released AMS-02 CR nuclei spectra of primary species (proton, helium, carbon, oxygen, neon, magnesium, silicon, and iron), secondary species (lithium, beryllium, boron, and fluorine), and hybrid species (nitrogen, sodium, and aluminum) and study the break positions and the spectral index differences (less and greater than the break rigidity) of the spectral hardening quantitatively. The results show us that the CR nuclei spectral hardening at a few hundred GV has hybrid origins. In detail, the dominating factors of the spectral hardening for primary and secondary CR nuclei species are different: the former comes from the superposition of different kinds of CR sources, while the latter comes from the propagation process. Both of these factors influence all kinds of CR nuclei spectra, just with different weights.", "keyphrases": ["cosmic ray composition", "cosmic ray energy spectrum", "cosmic ray propagation", "galactic cosmic rays", "origin of cosmic ray"]}
{"id": "lake2023problems", "title": "Problems with modified commutators", "abstract": "The purpose of this paper is to challenge the existing paradigm on which contemporary models of generalised uncertainty relations (GURs) are based, that is, the assumption of modified commutation relations. We review an array of theoretical problems that arise in modified commutator models, including those that have been discussed in depth and others that have received comparatively little attention, or have not been considered at all in the existing literature, with the aim of stimulating discussion on these topics. We then show how an apparently simple assumption can solve, or, more precisely, evade these issues, by generating GURs without modifying the basic form of the canonical Heisenberg algebra. This simplicity is deceptive, however, as the necessary assumption is found to have huge implications for the quantisation of space-time and, therefore, gravity. These include the view that quantum space-time should be considered as a quantum reference frame and, crucially, that the action scale characterising the quantum effects of gravity, \u03b2, must be many orders of magnitude smaller than Planck\u2019s constant, \u03b2 \u223c 10\u201361 \u00d7 \u210f, in order to recover the present day dark energy density. We argue that these proposals should be taken seriously, as a potential solution to the pathologies that plague minimum length models based on modified commutators, and that their implications should be explored as thoroughly as those of the existing paradigm, which has dominated research in this area for almost three decades.", "keyphrases": ["extended uncertainty principle", "generalised uncertainty principle", "generalised uncertainty relations", "minimum length", "minimum momentum", "modified commutation relations", "quantum geometry", "quantum gravity"]}
{"id": "vescovi2022neutron", "title": "Neutron-capture measurement candidates for the r-process in neutron star mergers", "abstract": "Neutron star mergers (NSMs) are one of the astrophysical sites for the occurrence of the rapid neutron capture process (r-process). After a merger, the ejected neutron-rich matter hosts the production of radioactive heavy nuclei located far from the stability valley. Their nuclear physics properties are key inputs for r-process nucleosynthesis calculations. Here, we focus on the importance of neutron-capture rates and perform a sensitivity study for typical outflows from NSMs. We identify the rates with the highest impact on the final r-process abundance pattern and the nuclear energy release, therefore determining the nucleosynthesis in NSMs. A list of major n-capture rates affecting individual isotopes and elements production is also provided.", "keyphrases": ["compact binary mergers", "gravitational waves", "kilonovae", "multimessenger astrophysics", "neutron - nuclear reactions", "neutron stars", "r-process"]}
{"id": "torrisi2022mm", "title": "Mm-wave polarimeter and profilometry design study for retrieving plasma density in the PANDORA experiment", "abstract": "In the recent past, the possibility to use a superconducting trap confining a hot and dense plasma as a tool to investigate radioactivity in astrophysical scenarios has been proposed. Making possible these kind of unprecedented measurements is the main aim of the PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) project. In this context, it is planned to build a compact and flexible magnetic plasma trap where plasma reaches an electron density ne \u223c 1011\u20131013 cm\u22123, and an electron temperature, in units of kT, kTe \u223c 0.1\u201330 keV. The setup is conceived to be able to measure, for the first time, nuclear \u03b2-decay rates in stellar-like conditions in terms of ionization states. In this paper, the design study of a mm-wave polarimeter for the PANDORA plasma line-integrated electron density measurement is presented. The paper highlights the method of this type of measurements for the first time proposed for a magneto-plasma trap which represents an \u201cintermediate\u201d case between the ultra-compact plasma ion sources and the large-size thermonuclear fusion devices. Preliminary measurements at scaled microwave frequencies have carried out both on a \u201cfree-space\u201d setup by using a wire-grid polarizer and a rotable Ka-band OMT + horn antennas system, and on a compact trap (called Flexible Plasma Trap) installed at INFN-LNS and used as PANDORA down-sized testbench are described. The polarimeter technique will support \u03b2-decay investigation by simultaneous measurements of the total plasma density, which is crucial to carefully evaluate the decay-constant and to extrapolate the laboratory observed data to the astrophysical scenarios. Moreover, this work proposes to adopt an electromagnetic inverse-scattering-based technique-based method to retrieve the electron density profile along the probing antennas line-of-sight. Numerical results of this so-called \u201cinverse profilometry\u201d are also shown.", "keyphrases": ["interferometry", "mm-wave", "orthomode transducers", "plasma diagnostics", "polarimeters", "profilometry"]}
{"id": "kerkeni2022qm", "title": "QM/MM Study of the H2 Formation on the Surface of a Water Ice Grain Doped With Formaldehyde: Molecular Dynamics and Reaction Kinetics", "abstract": "Formaldehyde has been widely observed in the icy mantle of interstellar grains. H2CO may be formed from successive hydrogenations of CO and may further contribute to the chemical complexity of the Interstellar medium (ISM) participating to heterogeneous reactions with colliding gas phase atoms. Within this context, Eley-Rideal and Langmuir-Hinshelwood rate constants of H2 formation on a formaldehyde doped amorphous water ice grain model of the ISM, were computed over a wide temperature range [15\u20132000 K]. We used classical molecular dynamics (MD) simulations to build the model of the H2CO doped ice surface. Then we studied theoretically by means of hybrid QM/MM ab initio and molecular mechanics methodology (ONIOM) H atoms abstraction from formaldehyde molecules and the H2 formation. Specifically, we investigate the reactivity of the gas phase H atom toward one formaldehyde molecule lying at one of the slab surfaces. The reaction path and the energetics are predicted, the mechanism is found to be exothermic by 14.89 kcal/mol and the barrier is 6.75 kcal/mol at the QM level CBS/DLPNO-CCSD(T)//ONIOM/aug-cc-pVTZ. We employ two approaches that take into account tunnelling and non-classical reflection effects by means of the Zero Curvature Tunnelling (ZCT), and the Small Curvature Tunnelling (SCT) which all provided comparable results to predict the kinetics of the reaction path. The rate constants show important quantum tunnelling effects at low temperatures when compared to rates obtained from the purely classical transition-state theory (TST) and from the canonical variational transition state theory (CVT). Corner cutting effects are highlighted in the SCT calculations by 4 to 5 orders of magnitude with respect to ZCT rate constants at low temperatures.", "keyphrases": ["astrochemistry", "formaldehyde", "ices", "quantum and classical modelling", "reaction rates"]}
{"id": "kerner2022domain", "title": "Domain-Agnostic Outlier Ranking Algorithms\u2014A Configurable Pipeline for Facilitating Outlier Detection in Scientific Datasets", "abstract": "Automatic detection of outliers is universally needed when working with scientific datasets, e.g., for cleaning datasets or flagging novel samples to guide instrument acquisition or scientific analysis. We present Domain-agnostic Outlier Ranking Algorithms (DORA), a configurable pipeline that facilitates application and evaluation of outlier detection methods in a variety of domains. DORA allows users to configure experiments by specifying the location of their dataset(s), the input data type, feature extraction methods, and which algorithms should be applied. DORA supports image, raster, time series, or feature vector input data types and outlier detection methods that include Isolation Forest, DEMUD, PCA, RX detector, Local RX, negative sampling, and probabilistic autoencoder. Each algorithm assigns an outlier score to each data sample. DORA provides results interpretation modules to help users process the results, including sorting samples by outlier score, evaluating the fraction of known outliers in n selections, clustering groups of similar outliers together, and web visualization. We demonstrated how DORA facilitates application, evaluation, and interpretation of outlier detection methods by performing experiments for three real-world datasets from Earth science, planetary science, and astrophysics, as well as one benchmark dataset (MNIST/Fashion-MNIST). We found that no single algorithm performed best across all datasets, underscoring the need for a tool that enables comparison of multiple algorithms.", "keyphrases": ["astrophysics", "earth science", "novelty detection", "out-of-distribution detection", "outlier detection", "planetary science"]}
{"id": "feng2022nebula", "title": "Nebula-Relay Hypothesis: The Chirality of Biological Molecules in Molecular Clouds", "abstract": "The chiral puzzle of biological molecules is thought to be closely related to the origin of life and is still a mystery so far. Previously, we proposed a new model on the origin of life, Nebula-Relay hypothesis, which assumed that the life on Earth originated at the planetary system of the Sun\u2019s predecessor star and then filled in the pre-solar nebula after its death. As primitive lives existed in the pre-solar nebula for a long time, did the chiral biomolecules form during this period? We explore such a possibility in this work and find that the ultra-low temperature environment of molecular clouds is beneficial to generating the chiral polymer chain of biological molecules.", "keyphrases": ["biological molecules", "chirality", "molecular cloud", "nebula-relay hypothesis", "peptide chain"]}
{"id": "stone2022nuclear", "title": "Nuclear Symmetry Energy and Hyperonic Stars in the QMC Model", "abstract": "The nuclear symmetry energy, together with the other saturation properties of symmetric nuclear matter, plays an important role in low energy nuclear structure of terrestrial systems, as well as astrophysical objects. In particular, its density dependence, both in sub- and supra-saturation regions in high density matter in neutron stars, is of utmost significance and has been a subject of active research for decades, usually within a mean-field framework. We report results obtained using the latest version of Quark-Meson-Coupling Model (QMC-A) with just three variable parameters, the baryon-meson coupling constants in free space. It is shown that these parameters can be determined directly using nuclear matter (NM) properties at saturation; two parameters of symmetric nuclear matter (SNM), the baryon number density and the energy per particle, and the symmetry energy coefficient of asymmetric nuclear matter (ANM). The effects of uncertainties in the these parameters and propagation of these uncertainties through the calculation of properties of dense hyperonic matter and cold neutron stars are demonstrated. This approach leads to new limits on both the NM parameters and the QMC coupling constants. The results, which exploit the unique features of the QMC model, are discussed and future prospects are outlined.", "keyphrases": ["high density equation of state", "hyperonic stars", "neutron stars", "quark-meson-coupling model", "symmetry energy"]}
{"id": "puzzarini2022gas", "title": "Gas-phase Chemistry in the Interstellar Medium: The Role of Laboratory Astrochemistry", "abstract": "\u201cWho\u201d and how? In this simple question the complexity of the interstellar chemistry is encapsulated. \u201cWho\u201d refers to what molecules are present in the interstellar medium (ISM) and \u201chow\u201d to the mechanisms that led to their formation. While the large number of molecules discovered in the ISM (\u223c250) demonstrates the rich chemistry occurring there, a significant number of unknown species are waiting for an identification and the processes that led to the synthesis of the identified species are still hotly debated or even unknown. Gas-phase laboratory studies in the fields of rotational spectroscopy and quantum chemistry provide an important contribution to answering the question above. An overview on the role played by rotational spectroscopy and quantum chemistry in the unraveling of the gas-phase chemistry of the interstellar medium is presented.", "keyphrases": ["astrochemistry", "gas-phase reactivity", "ism", "prebiotic molecules", "rotational spectroscopy"]}
{"id": "gibson2022using", "title": "Using Multivariate Imputation by Chained Equations to Predict Redshifts of Active Galactic Nuclei", "abstract": "Redshift measurement of active galactic nuclei (AGNs) remains a time-consuming and challenging task, as it requires follow up spectroscopic observations and detailed analysis. Hence, there exists an urgent requirement for alternative redshift estimation techniques. The use of machine learning (ML) for this purpose has been growing over the last few years, primarily due to the availability of large-scale galactic surveys. However, due to observational errors, a significant fraction of these data sets often have missing entries, rendering that fraction unusable for ML regression applications. In this study, we demonstrate the performance of an imputation technique called Multivariate Imputation by Chained Equations (MICE), which rectifies the issue of missing data entries by imputing them using the available information in the catalog. We use the Fermi-LAT Fourth Data Release Catalog (4LAC) and impute 24", "keyphrases": ["agns", "blls", "fermi 4lac", "fsrqs", "imputation", "machine learning regressors", "mice", "redshift"]}
{"id": "\u010furech2022rotation", "title": "Rotation Periods of Asteroids Determined With Bootstrap Convex Inversion From ATLAS Photometry", "abstract": "The rotation period is one of the fundamental physical characteristics of asteroids. It can be determined from photometric measurements by standard methods of time-series period analysis or by creating a physical model of an asteroid with the rotation period being one of the fitted parameters. We used the latter approach to determine the sidereal rotation period for more than 5000 asteroids, out of which about 1600 are those for which their period was not known. We processed photometric measurements of about 100,000 asteroids from the ATLAS survey with the light curve inversion technique in the Asteroids@home project to search for the best-fit rotation period. This was repeated 25 times with randomly resampled\u2014bootstrapped\u2014data. For thousands of asteroids, their best-fit period was the same for most of the bootstrapped data sets; thus, their rotation period was determined with a high degree of reliability.", "keyphrases": ["asteroids", "bootstrap", "light curves", "photometry", "surveys"]}
{"id": "yndestad2022jovian", "title": "Jovian Planets and Lunar Nodal Cycles in the Earth\u2019s Climate Variability", "abstract": "This study utilizes time-series data devised to measure solar irradiation, sea surface temperatures, and temperatures in the lower atmosphere to gain a better understanding of how gravitational effects from the moon and Jovian planets (Jupiter, Saturn, Uranus, and Neptune) influence solar activity and climatic conditions on Earth. Then, standard statistical methods are used to determine the degree of correlation among these time series and construct a Jovian gravitational model. The study reveals a direct relationship between JSUN perihelion coincidences and TSI amplitude variations in cycles up to 4,450 years. The forced solar accumulation of heat in oceans introduces a new phase relation between solar forced cycles and new climate variation. Earth\u2019s axis nutation cycles have coincidences with lunar nodal tide cycles and lunar forced sea surface temperature cycle periods up to 446 years. Earth\u2019s temperature variation shows coincidence with constructive and destructive interference between lunar-forced and accumulated solar-forced temperature variations in oceans. Upcoming events have a computed modern temperature maximum in 2025 and a deep minimum in 2070. Interference between solar-forced temperature cycles of 333,2142, and 4,450 years and a lunar-forced temperature cycle of 445 years indicates that \u201cThe Little Ice Age\u201d covers a total period of 820 years from 1330 to 2150 A.D. and an upcoming temporary cold climate period from 2070 to 2150.", "keyphrases": ["climate variability", "deep solar minima", "jovian planet variations", "lunar nodal cycle spectrum", "solar-lunar-forced climate variation", "tsi variations"]}
{"id": "ghosh2022multi", "title": "Multi-Physics Constraints at Different Densities to Probe Nuclear Symmetry Energy in Hyperonic Neutron Stars", "abstract": "The appearance of strangeness in the form of hyperons within the inner core of neutron stars is expected to affect its detectable properties, such as its global structure or gravitational wave emission. This work explores the parameter space of hyperonic stars within the framework of the Relativistic Mean Field model allowed by the present uncertainties in the state-of-the-art nuclear and hypernuclear experimental data. We impose multi-physics constraints at different density regimes to restrict the parameter space: Chiral effective field theory, heavy-ion collision data, and multi-messenger astrophysical observations of neutron stars. We investigate possible correlations between empirical nuclear and hypernuclear parameters, particularly the symmetry energy and its slope, with observable properties of neutron stars. We do not find a correlation for the hyperon parameters and the astrophysical data. However, the inclusion of hyperons generates a tension between the astrophysical and heavy-ion data constraining considerably the available parameter space.", "keyphrases": ["equation of state", "heavy-ion", "hypernuclear", "hyperons", "multi-messenger", "neutron stars", "nuclear", "symmetry energy"]}
{"id": "miklav\u010di\u010d2022habitat", "title": "Habitat Bennu: Design Concepts for Spinning Habitats Constructed From Rubble Pile Near-Earth Asteroids", "abstract": "The authors explore the possibility that near-earth, rubble pile asteroids might be used as habitats for human settlement by increasing their rotation to produce spin gravity. Using previously published scaling by Maindl et al. and studies of asteroid populations, it is shown that there is no class of hollowed body that would survive the spin-up process on its own without additional reinforcement. Large solid-rock asteroids (diameter D > 10 km) would not have the tensile strength to withstand the required rotation rates and would fracture and break apart. Smaller asteroids, being \u2018rubble piles\u2019, have little tensile strength and would quickly disperse. The possibility of containing the asteroid mass using higher-strength materials like carbon nanofiber is instead considered. It is found that a moderate tensile strength container can maintain the integrity of a large spinning cylinder composed of dispersed asteroid regolith. The research extends the range of possible asteroid habitat candidates, since it may become feasible to construct habitats from the more numerous smaller bodies, including NEAs (Near Earth Asteroids). The required tensile strength of the container material scales with habitat radius and thickness and is \u223c 200 MPa for a starting asteroid body of radius 300 m that is spun up to provide 0.3 g\u2295 while increasing its radius to 3 km and maintaining a rubble and regolith shield thickness of 2 m to protect against cosmic rays. Ambient solar power can be harvested to aid in spin-up and material processing.", "keyphrases": ["finite element analysis", "habitat design", "hoop stress", "near earth asteroids", "numerical simulations", "rubble pile asteroids"]}
{"id": "penttil\u00e42022taxonomy", "title": "Taxonomy of Asteroids From the Legacy Survey of Space and Time Using Neural Networks", "abstract": "The Legacy Survey of Space and Time (LSST) is one of the ongoing or future surveys, together with the Gaia and Euclid missions, which will produce a wealth of spectrophotometric observations of asteroids. This article shows how deep learning techniques with neural networks can be used to classify the upcoming observations, particularly from LSST, into the Bus-DeMeo taxonomic system. We report here a success ratio in classification up to 90.1", "keyphrases": ["asteroids", "legacy survey of space and time", "neural network", "spectra", "taxonomy"]}
{"id": "bank2022scaling", "title": "Scaling, Mirror Symmetries and Musical Consonances Among the Distances of the Planets of the Solar System", "abstract": "Orbital systems are often self-organized and/or characterized by harmonic relations. Inspired by music theory, we rewrite the Geddes and King-Hele (QJRAS, 24, 10\u201313, 1983) equations for mirror symmetries among the distances of the planets of the Solar System in an elegant and compact form by using the 2/3rd power of the ratios of the semi-major axis lengths of two neighboring planets (eight pairs, including the belt of the asteroids). This metric suggests that the Solar System could be characterized by a scaling and mirror-like structure relative to the asteroid belt that relates together the terrestrial and Jovian planets. These relations are based on a 9/8 ratio multiplied by powers of 2, which correspond musically to the interval of the Pythagorean epogdoon (a Major Second) and its addition with one or more octaves. Extensions of the same model are discussed and found compatible also with the still hypothetical vulcanoid asteroids versus the transneptunian objects. The found relation also suggests that the planetary self-organization of our system could be generated by the 3:1 and 7:3 resonances of Jupiter, which are already known to have shaped the asteroid belt. The proposed model predicts the main Kirkwood asteroid gaps and the ratio among the planetary orbital parameters with a 99", "keyphrases": ["music and astronomy", "orbital resonances", "orbital self-organization", "orbital symmetries", "solar system"]}
{"id": "ragusa2022intra", "title": "The Intra-Group Baryons in the LEO I Pair From the VST Early-Type GAlaxy Survey", "abstract": "In this paper we present the deep, wide-field and multi-band imaging of the LEO I pair NGC 3379-NGC 3384, from the VST Early-type GAlaxy Survey (VEGAS). The main goal of this study is to map the intra-group baryons in the pair, in the form of diffuse light and globular clusters (GCs). Taking advantage from the large covered area, which extends for \u223c 3.9 square degrees around the pair, and the long integration time, we can map the light distribution out to \u223c 63 kpc and down to \u223c 30 mag/arcsec2 in the g band and \u223c 29 mag/arcsec2 in the r band, deeper than previous data available for this target. The map of the intra-group light (IGL) presents two very faint (\u03bcg \u223c 28-29 mag/arcsec2) streams protruding from the brightest group member NGC 3379 and elongated toward North-West and South. We estimate that the fraction of the stellar halo around NGC 3379 plus the intra-group light is (Formula presented.) in both g and r bands, with an average color g-r = 0.75 \u00b1 0.04 mag. The color distribution of the GCs appears multi-modal, with two dominant peaks at (u-r) = 1.8 mag and (u-r) = 2.1 mag, respectively. The GC population stretches from North-East to South-West and from North-West to South of the pair, in the last case overlapping with the streams of IGL, as well as the PNe distribution found by Hartke et al. (Hartke et al., A   A, 2020, 642, A46) and Hartke et al. (Hartke et al., 2022). Since these structures are elongated in the direction of the two nearby galaxies M96 and NGC 3338, they could be the remnant of a past gravitational interactions with the pair.", "keyphrases": ["diffuse intragroup light", "evolution -galaxies", "galaxies", "general -galaxies", "group", "interactions-intergalactic medium -galaxies", "surface photometry -galaxies"]}
{"id": "garofalo2022origin", "title": "The Origin and Evolution of Giant Radio Galaxies", "abstract": "Giant radio galaxies are arguably the least understood of jetted active galactic nuclei (AGN). We propose that radio galaxies are the product of large mergers that do not involve radio galaxies or radio quasars, such as in merging spiral galaxies, while giant radio galaxies emerge from a merger involving a parent that in the not-too-distant past harbored a radio galaxy. Predictions following from this are an upper limit to the number fraction of giant radio galaxies to radio galaxies, lower average redshift for giant radio galaxies, a higher incidence of high excitation for giant radio galaxies compared with radio galaxies, and lower average prograde black hole spin values for giant radio galaxies compared to radio galaxies and to bright radio quiet quasars.", "keyphrases": ["accretion disks - radio continuum", "active\u2014galaxies", "black holes", "jets - accretion", "radio galaxies"]}
{"id": "nicolaou2022resolving", "title": "Resolving Space Plasma Species With Electrostatic Analyzers", "abstract": "Electrostatic analyzers resolve the energy-per-charge distributions of charged plasma particles. Some space plasma instruments use electrostatic analyzers among other units, such as aperture deflectors and position sensitive detectors, in order to resolve the three-dimensional energy (velocity) distribution functions of plasma particles. When these instruments do not comprise a mass analyzer unit, different species can be resolved only if there are measurable differences in their energy-per-charge distributions. This study examines the ability of single electrostatic analyzer systems in resolving co-moving plasma species with different mass-per-charge ratios. We consider examples of static plasma consisting of two species of heavy negative ions measured by a typical electrostatic analyzer design, similar to the electron spectrometer on board Cassini spacecraft. We demonstrate an appropriate modeling technique to simulate the basic features of the instrument response in the specific plasma conditions and we quantify its ability to resolve the key species as a function of the spacecraft speed and the plasma temperature. We show that for the parameter range we examine, the mass resolution increases with increasing spacecraft speed and decreasing plasma temperature. We also demonstrate how our model can analyze real measurements and drive future instrument designs.", "keyphrases": ["instrumentation", "methods", "planetary physics", "plasma modeling", "plasma physics"]}
{"id": "rivilla2022molecular", "title": "Molecular Precursors of the RNA-World in Space: New Nitriles in the G+0.693\u22120.027 Molecular Cloud", "abstract": "Nitriles play a key role as molecular precursors in prebiotic experiments based on the RNA-world scenario for the origin of life. These chemical compounds could have been partially delivered to the young Earth from extraterrestrial objects, stressing the importance of establishing the reservoir of nitriles in the interstellar medium. We report here the detection towards the molecular cloud G+0.693\u22120.027 of several nitriles, including cyanic acid (HOCN), and three C4H3N isomers (cyanoallene, CH2CCHCN; propargyl cyanide, HCCCH2CN; and cyanopropyne (CH3CCCN), and the tentative detections of cyanoformaldehyde (HCOCN), and glycolonitrile (HOCH2CN). We have also performed the first interstellar search of cyanoacetaldehyde (HCOCH2CN), which was not detected. Based on the derived molecular abundances of the different nitriles in G+0.693\u22120.027 and other interstellar sources, we have discussed their formation mechanisms in the ISM. We propose that the observed HOCN abundance in G+0.693\u22120.027 is mainly due to surface chemistry and subsequent shock-induced desorption, while HCOCN might be mainly formed through gas-phase chemistry. In the case of HOCH2CN, several grain-surface routes from abundant precursors could produce it. The derived abundances of the three C4H3N isomers in G+0.693\u22120.027 are very similar, and also similar to those previously reported in the dark cold cloud TMC-1. This suggests that the three isomers are likely formed through gas-phase chemistry from common precursors, possibly unsaturated hydrocarbons (CH3CCH and CH2CCH2) that react with the cyanide radical (CN). The rich nitrile feedstock found towards G+0.693\u22120.027 confirms that interstellar chemistry is able to synthesize in space molecular species that could drive the prebiotic chemistry of the RNA-world.", "keyphrases": ["astrochemistry", "molecular clouds", "molecules-ism", "prebiotic chemisitry", "rna-world"]}
{"id": "barone2022accurate", "title": "Toward Accurate Formation Routes of Complex Organic Molecules in the Interstellar Medium: The Paradigmatic Cases of Acrylonitrile and Cyanomethanimine", "abstract": "The investigation of reaction mechanisms in the interstellar medium requires the evaluation of reaction rates and branching ratios, which can be effectively obtained in the framework of the ab-initio transition state/master equation formalism. However, the reliability of this approach relies on the computation of accurate reaction enthalpies and activation energies for all the paths characterizing the potential energy surface under investigation. Two effective yet reliable parameter-free model chemistries are introduced to obtain accurate energies of all stationary points, with structural determination performed using double-hybrid density functionals. After their validation, these model chemistries have been employed to analyze the competition between hydrogen abstraction and addition/elimination in the reaction between the CN radical and ethylene or methanimine. The energetics has then been complemented by a kinetic study. The results provide new information about important reactive channels operative in different regions of the interstellar medium and in the atmospheres of exoplanets. These further extend the recent general addition/elimination mechanism for the formation of \u201ccomplex imines\u201d from the reaction of methanimine with a small radical species.", "keyphrases": ["complex organic molecules", "formation mechanisms", "interstellar medium", "quantum-chemical composite schemes", "radical additions", "reaction rates"]}
{"id": "wu2022squab", "title": "SQUAB\u2014I: The First Release of Strange QUasar Candidates With ABnormal Astrometric Characteristics From Gaia EDR3 and SDSS", "abstract": "Given their extremely large distances and small apparent sizes, quasars are generally considered as objects with near-zero parallax and proper motion. However, some special quasars may have abnormal astrometric characteristics, such as quasar pairs, lensed quasars, AGNs with bright parsec-scale optical jets, which are scientifically interesting objects, such as binary black holes. These quasars may come with astrometric jitter detectable with Gaia data, or significant changes in the position at different wavelengths. In this work, we aim to find these quasar candidates from Gaia EDR3 astrometric data combining with Sloan Digital Sky Survey (SDSS) spectroscopic data to provide a candidate catalog to the science community. We propose a series of criteria for selecting abnormal quasars based on Gaia astrometric data. We obtain two catalogs containing 155 sources and 44 sources, respectively. They are potential candidates of quasar pairs.", "keyphrases": ["astrometry", "catalogs", "quasar pairs", "quasars", "reference frame"]}
{"id": "wang2022coronal", "title": "From Coronal Holes to Pulsars and Back Again: Learning the Importance of Data", "abstract": "Although wanting to become an astronomer from an early age, I ended up in solar physics purely by chance, after first working in high-energy astrophysics. I\u2019ve never regretted switching from the pulsar to the solar magnetosphere, because solar physics has a great advantage over other areas of astrophysics\u2014in the enormous amount of high-quality data available, much of it underutilized. I\u2019ve often wondered why theoreticians and modelers don\u2019t spent more time looking at these data (perhaps they feel that it is cheating, like taking a peek at the answers to a difficult homework assignment?). Conversely, I wonder why observers and data analysts aren\u2019t more skeptical of the theoretical models\u2014especially the fashionable ones.", "keyphrases": ["coronal heating", "coronal holes", "coronal loops", "magnetograms", "solar dynamo", "solar wind"]}
{"id": "myrzakulov2022analysis", "title": "Analysis of Reconstructed Modified Symmetric Teleparallel f(Q) Gravity", "abstract": "The existing analysis reports a reconstruction scheme of the newly proposed gravity say f(Q) gravity through the scale factor of the form (Formula presented.) by describing the power-law cosmology. The reconstructed f(Q) gravity models disclosed how this modified gravity model is capable to replicate dissimilar epochs of the cosmological history. Also, the reconstructed f(Q) gravity models are castoff to develop the expressions for density and pressure and the equation of state parameter. We reconstruct two cases of interacting fluid scenario ghost and pilgrim dark energy with pressureless dark matter. The physical behavior of the models is talked over the evolution of the Universe is accelerated. Moreover, the well-known cosmological planes i.e., (Formula presented.) and (r \u2212 s) constructed for our models, also include a comparison of our findings of these dynamical parameters with observational constraints. It is also quite interesting to mention here that the results of the equation of state parameter, (Formula presented.) and (r \u2212 s)-planes coincide with the modern observational data.", "keyphrases": ["cosmological evolution", "f (q) gravity", "ghost dark energy", "isotropic homogeneous space-time", "non-metricity scalar", "pilgrim dark energy"]}
{"id": "jim\u00e9nez_serra2022ska", "title": "The SKA as a Prebiotic Molecule Detector", "abstract": "One of the theories for the origin of life proposes that a significant fraction of prebiotic material could have arrived to Earth from outer space between 4.1 and 3.8 billion years ago. This suggests that those prebiotic compounds could have originated in interstellar space, to be later on incorporated to small Solar-system bodies and planetesimals. The recent discovery of prebiotic molecules such as hydroxylamine and ethanolamine in the interstellar medium, strongly supports this hypothesis. However, some species such as sugars, key for the synthesis of ribonucleotides and for metabolic processes, remain to be discovered in space. The unmatched sensitivity of the Square Kilometre Array (SKA) at centimeter wavelengths will be able to detect even more complex and heavier prebiotic molecules than existing instrumentation. In this contribution, we illustrate the potential of the SKA to detect simple sugars with three and four carbon atoms, using a moderate investment of observing time.", "keyphrases": ["astrochemistry", "complex organic molecules", "interstellar medium", "prebiotic chemistry", "square kilometre array"]}
{"id": "muinonen2022asteroid", "title": "Asteroid Photometric Phase Functions From Bayesian Lightcurve Inversion", "abstract": "Photometry is an important tool for characterizing the physical properties of asteroids. An asteroid\u2019s photometric lightcurve and phase curve refer to the variation of the asteroid\u2019s disk-integrated brightness in time and in phase angle (the Sun-asteroid-observer angle), respectively. They depend on the asteroid\u2019s shape, rotation, and surface scattering properties, and the geometry of illumination and observation. We present Bayesian lightcurve inversion methods for the retrieval of the asteroid\u2019s phase function, the unambiguous phase curve of a spherical object with surface scattering properties equal to those of the asteroid. A collection of such phase functions can give rise to a photometric taxonomy for asteroids. In the inverse problem, first, there are four classes of lightcurves that require individual error models. The photometric observations can be absolute or relative and they can have dense or sparse cadence in comparison to the rotation period of the asteroid. Second, the observations extend over varying phase angle ranges, requiring different phase function models. Asteroid photometry from the European Space Agency Gaia space mission extends, typically, over a range of phase angles, where the phase curve tends to be linear on the magnitude scale. Photometry from ground-based observing programs can reach small phase angles, where the asteroids show an opposition effect, a nonlinear increase of brightness on the magnitude scale towards zero phase angle. We provide error models for all four classes of lightcurves and make use of linear or linear-exponential phase functions for phase angles below 50\u00b0. We apply the inverse methods to sparse absolute Gaia and dense relative ground-based lightcurves and obtain absolute magnitudes and phase functions, with uncertainties, for \u223c500 asteroids. Finally, we assess the lightcurve inversion problem for dense absolute photometry with the help of a numerical simulation for a Gaussian-random-sphere asteroid.", "keyphrases": ["absolute magnitude", "asteroid", "asteroid taxonomy", "convex inversion", "gaia mission", "lightcurve", "phase curve", "phase function"]}
{"id": "gonz\u00e1lez2022gas", "title": "Gas-Phase Reactivity of OH Radicals With Ammonia (NH3) and Methylamine (CH3NH2) at Around 22 K", "abstract": "Interstellar molecules containing N atoms, such as ammonia (NH3) and methylamine (CH3NH2), could be potential precursors of amino acids like the simplest one, glycine (NH2CH2COOH). The gas-phase reactivity of these N-bearing species with OH radicals, ubiquitous in the interstellar medium, is not known at temperatures of cold dark molecular clouds. In this work, we present the first kinetic study of these OH-reactions at around 22 K and different gas densities [(3.4\u201316.7) \u00d7 1016 cm\u22123] in helium. The obtained rate coefficients, with \u00b1 2\u03c3 uncertainties, can be included in pure gas-phase or gas-grain astrochemical models to interpret the observed abundances of NH3 and CH3NH2. We observed an increase of k1 and k2 with respect to those previously measured by others at the lowest temperatures for which rate coefficients are presently available: 230 and 299 K, respectively. This increase is about 380 times for NH3 and 20 times for CH3NH2. Although the OH + NH3 reaction is included in astrochemical kinetic databases, the recommended temperature dependence for k1 is based on kinetic studies at temperatures above 200 K. However, the OH + CH3NH2 reaction is not included in astrochemical networks. The observed increase in k1 at ca. 22 K does not significantly change the abundance of NH3 in a typical cold dark interstellar cloud. However, the inclusion of k2 at ca. 22 K, not considered in astrochemical networks, indicates that the contribution of this destruction route for CH3NH2 is not negligible, accounting for 1/3 of the assumed main depletion route (reaction with HCO+) in this IS environment. (Formula presented.) (Formula presented.).", "keyphrases": ["cresu technique", "ism", "oh radicals", "prebiotic molecules", "reaction kinetics", "ultralow temperatures"]}
{"id": "ho2022interplanetary", "title": "Interplanetary Ion Flux Dropouts Across Multiple 3He-Rich Events", "abstract": "Solar Orbiter, a joint ESA/NASA mission, is studying the Sun and inner heliosphere in greater detail than ever before. Launched in February 2020, Solar Orbiter has already completed its first three orbits, reaching perihelia of 0.5 au from the Sun in June 2020, February and August 2021. During the first 2 years in orbit, Solar Orbiter observed multiple 3He-rich Solar Energetic Particle (SEP) events inside 1 au. Even though these events were small, their spectral forms, 3He content, and association with energetic electrons and type III bursts convincingly identifies them as 3He-rich SEP events with properties similar to those previously observed at 1 au, and promising new insights as Solar Orbiter moves much closer to the Sun in 2022. In May 2021, we observed six 3He-rich SEP events in close succession within 48 h when Solar Orbiter was at 0.95 au. These events were likely released from the same active region at the Sun, and the particles arrived at Solar Orbiter in two batches with various abundances and intensities, showing strong anisotropies throughout. Multiple ion flux dropouts were also observed with these six 3He-rich SEP events. The fact that we observed so many ion injections in such a short period of time indicates the 3He enrichment and acceleration mechanism can produce SEP from the same region very efficiently and with varying enrichment levels and intensities. In addition, we report for the first-time dropout features that spanned multiple ion events simultaneously. This implies the field line random walk that we observe at 1 au still maintains magnetic connections to a small region back at the Sun up to the entire duration of these events (\u223c48 h).", "keyphrases": ["3he-rich events", "active region", "energetic particle", "particle acceleration", "solar orbiter mission", "sun"]}
{"id": "brahma2022bulk", "title": "Bulk Viscous Bianchi Type-V Cosmological Model in f(R, T) Theory of Gravity", "abstract": "This paper deals with the bulk viscous Bianchi type-V cosmological model with an exponential scale factor in Lyra geometry based on f(R, T) gravity, by considering a time dependent displacement field. To determine the nature and physical properties of the model, we considered Harko et al. (Harko et al., Phys. Rev. D, 2011, 84, 024020) [proposed the linear form f(R, T) = f1(R) + f2(T)], in which the barotropic equation of state for pressure, density, and bulk viscous pressure is proportional to energy density. The kinematical properties of the model are also discussed in the presence of bulk viscosity. Evolution of energy conditions is also studied and examined the behaviour of that in examined in order to explain the late-time cosmic acceleration.", "keyphrases": ["bianchi type-v", "bulk viscous", "dark energy", "f(r", "t) gravity", "lyra geometry", "\u03bb cdm model"]}
{"id": "gigoyan2023tyc", "title": "TYC 1417-891-1 and TYC 1478-742-1: Eclipsing Variable Stars. The Gaia EDR3 and TESS Photometric Data", "abstract": "Based on the TESS (Transiting Exoplanet Survey Satellite) phase dependent light curves, we confirm the eclipsing type variability nature for two G-type dwarfs: TYC 1417-891-1 and TYC 1478-742-1. Both objects show EA (Algol-type) light curves morphology. Orbital period for TYC 1417-891-1 is P \u2248 8.0 day and for TYC 1478-742-1, P \u2248 13.6 day. We present Gaia EDR3 and TESS catalogue important physical parameters as well as LAMOST spectra. Both objects are relatively bright and are located at a distance of 260.59 (\u00b13.21) pc (TYC 1417-891-1) and 117.42 (\u00b10.74) pc (TYC 1478-742-1). The TESS light curve of TYC 1478-742-1 shows also flares as well. We discuss possible nature of the secondary and faint objects around these stars.", "keyphrases": ["eclipsing variables", "tess and gaia data", "variables"]}
{"id": "vinutha2023study", "title": "The Study of Kantowski-Sachs Perfect Fluid Cosmological Model in Modified Gravity", "abstract": "Kantowski-Sachs perfect fluid cosmological model is explored in modified gravity with functional form f (R, T) = f1(R) + f2 (T) where R is Ricci scalar and T is the trace of energymomentum tensor. With this functional form, three different cases have been formulated, namely negative and positive powers of curvature, logarithmic curvature and exponential curvature given by f1 (R) = R + \u03b3 R2 \u2013 \u03bc4 / R, f1(R) = R+ v ln(\u03c4R) and f1(R) = R+ \u03bae\u2013\u03b9R respectively, and for all these three cases, f2 (T) = \u03bbT, here \u03b3,\u03bb,\u03bc,v,\u03c4,\u03ba and \u03b9 are constants. While solving the field equations, two constraints i) Expansion scalar is proportional to shear scalar ii) Hyperbolic scale factor are used. By using these conditions the required optimum solutions are obtained. The physical parameters are calculated and geometrical parameters of three cases are analysed against redshift z with the help of pictorial representation. In the context of f (R, T) gravity energy conditions are discussed with the help of pressure and energy density. If strong energy condition is positive the gravity should be attractive but in our model it is negative. It means that cosmic acceleration is due to antigravity, whereas NEC and DEC are fulfilled. The perturbation technique is used to test the stability of the background solutions of the obtained models. The inferences obtained from this paper are in persistent with the present cosmological observations and the model represents an accelerating universe.", "keyphrases": ["f (r", "kantowski-sachs spacetime", "perfect fluid", "t) theory"]}
{"id": "savanov2023activity1", "title": "Activity of the Young Star EPIC 204376071 from the Upper SCO Association", "abstract": "Based on observations from the K2 mission of the Kepler Space Telescope a study is made of the activity of EPIC 204376071, a young object in the Upper SCO association with an age of 11\u00b13 million years whose light curve has a single darkening lasting one day with a depth of about 80", "keyphrases": ["activity", "flares", "occultation", "photometry", "spots", "stars", "variability"]}
{"id": "bondar2022periodic", "title": "Periodic Variations in the Brightness of the Red Dwarf V647 Her", "abstract": "Photometric series for the red dwarf V647 Her (M3.5V) obtained from observations in 2019 at the Crimean Astrophysical Observatory and from data in the SuperWASP calalog in 2004-2007 are analyzed. Analysis of the examined light curves reveals the presence of a variability with an amplitude of 0m.04 and a period of 20.69 days. The stability of the characteristics of this variability in different epochs is studied. The amplitude of the variability and the phase of the minimum is preserved for an interval of 40-60 days. After deduction of the contribution of the 20-day periodicity, in the residuals of 2019 are suspected rapid changes with a period of 1.1 days with a probability of about 95", "keyphrases": ["flare stars", "photometric variability", "red dwarfs", "stars", "v647 her"]}
{"id": "alaverdyan2023effect", "title": "Effect of Neutrino Oscillations on the Thermodynamic Properties of Hot Quark Matter", "abstract": "The effect of neutrino oscillations on the thermodynamic characteristics of three-flavor hot quark matter in \u03b2-equilibrium that is opaque for neutrinos is examined in terms of the local SU(3) Nambu-Jona-Lasinio (NJL) model which also accounts for the \u2018t Hooft interaction that leads to quark flavor mixing. The thermodynamic characteristics of quark matter are determined for two temperatures, T = 60 and 100 MeV, with neutrino oscillations taken into account. These results are compared with those obtained without taking neutrino oscillations into account. The calculations show that during cooling of quark matter that is opaque to neutrinos, the energy released per unit of baryon charge is 150 \u00f7 350 MeV.", "keyphrases": ["hot quark matter", "neutrino oscillations", "njl model", "trapped neutrinos"]}
{"id": "hajyan2022properties", "title": "Properties of Hot Quark Matter with Neutrino Confinement in the NJL Model", "abstract": "The thermodynamic characteristics of hot \u03b2-equilibrium three-flavor quark matter with neutrino confinement are studied in terms of the local SU(3) Nambu-Jona-Lasinio (NJL) model, which also accounts for the \u2018t Hooft interaction which leads to mixing of quark flavors. For different temperatures T \u2208 [20 \u00f7100] MeV and baryon number densities nB \u2208 [0 \u00f7 1.8] fm-3 the constituent quark masses, quark condensates, and relative contributions of individual types of particles to the pressure and chemical potentials of the constituent particles are determined. In order to determine the role of neutrinos in the hot quark matter, the pressures and energies in states with and without neutrinos are compared.", "keyphrases": ["equation of state", "hot quark matter", "neutrino confinement", "njl model"]}
{"id": "larchenkova2022observational", "title": "Observational Manifestations of First Galaxies in the Far Infrared Range", "abstract": "High-redshift galaxies (z \u2273 9) are currently observed in the near-infrared (1.4-2 \u03bcm), mid-infrared (IR) (5-28.8 \u03bcm), and submillimeter (500-1000 \u03bcm) ranges. The far IR band, which carries important information on fundamental processes in early galaxies corresponding to the mid-infrared range in the restframe is hidden from the observer by the earth\u2019s atmosphere. We consider the parameters of the emission from galaxies at high redshifts and the possibility of observing them in the far IR using gravitational lensing on massive galactic clusters. The emission presumably arises predominantly in gas ionized by ultraviolet (UV) and X-ray emission of stars and the central supermassive black holes (SMBH) of host galaxy. The metallicity of the gas of the parent galaxies lies within an interval of -6 \u2264 [Z/H] \u2264 -1, as follows from observations of distant galaxies at (z \u2273 9). We estimate the spectral features in the far IR range and the conditions under which these galaxies can be detected. It is shown that the spectral lines Pf-\u03b1 and Hm-\u03b1, along with several lines of metals in the mid IR range ([NeV] I7.6, [SIV] 10.5, [NeIII] 15.6, [NeV] 24.1, [OIV] 25.8 \u03bcm, etc.), can be sufficiently bright to be detected. With using gravitational lensing on known galactic clusters, the number of expected high-redshift candidates in the far IR is large enough to carry out a program of observations on the \u201cMillimetron\u201d Space Observatory in the 70-500 \u03bcm wavelength range.", "keyphrases": ["far ir range", "first galaxies", "gravitational lensing on galactic clusters", "hydrogen spectral lines", "supermassive black holes"]}
{"id": "nagirner2022compton1", "title": "Compton Scattering in Plane Media: Polarization of Radiation and Azimuth Independence. I. Theory", "abstract": "Compton scattering of polarized radiation by a nondegenerate and unpolarized electron gas is examined. Two polarization bases are introduced for pulses of photons: external, connected with the geometry of the medium and internal, connected with a scattering event. Starting with a general relativistic kinetic equation describing the multiple effect of the mechanism taking induced processes into account, it is shown that for describing a stationary, azimuthally independent radiation field in a plane layer, two Stokes parameters for linear polarization are sufficient. The features of the redistribution functions (RF) in frequency and direction are clarified, as well as the rotation angles from internal bases to external ones, and back which arise with forward and backward scattering. An algorithm is proposed for eliminating singularities during azimuthal averaging. The azimuthal averages from the most singular term of the RF are expressed in terms of elliptical integrals of the first kind.", "keyphrases": ["compton scattering", "frequency redistribution functions", "radiative transfer", "stokes parameters"]}
{"id": "fursyak2022electric", "title": "Electric Current Systems in Active Regions at a Late Stage of Evolution and Their Role in the Processes of Stabilization/Destabilization of Sunspots", "abstract": "Data from the Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamic Observatory (SDO) on the components of the magnetic field vector in the sun\u2019s photosphere are obtained for 46 active regions (AR) in the final stage of evolution to calculate the magnitudes of the horizontal, vertical, and large-scale electric current at the solar photosphere level. In each case the dynamics of the parameters of the electric current over the time the regions are within \u00b135\u00b0 from the central solar meridian was studied. The parameters of the electric current with the decay rate of the magnetic flux in a sunspot was compared. The following results are obtained: (1) a direct relationship between the value of the average unsigned density of the local vertical electric currents and the decay rate of the magnetic flux in a spot with a correlation coefficient of k = 0.56 was found. (2) A nonzero large-scale electric current only in ARs with a relatively low decay rate of the magnetic flux in a sunspot (not exceeding the value 6.0\u22191019 Mx h-1) was detected. Thus, a large-scale electric current can have a stabilizing effect on a sunspot without being the only mechanism for stabilizing sunspots, since only for the 37", "keyphrases": ["active regions", "electric currents", "magnetic field", "sun"]}
{"id": "chandra2022n", "title": "N-S Asymmetry and Periodicity of Daily Sunspot Number During Solar Cycles 22-24", "abstract": "In this paper, a broad examination of the N-S asymmetry of daily sunspot numbers during the period January 1992 to March 2020 has been performed, examining its statistical significance and looking for the short term periodicity of daily sunspot numbers using the Fast Fourier Transform (FFT) during solar cycle 22 (1 January 1986 to 27 August 1996), cycle 23 (28 August 1996 to 10 December 2008) and cycle 24 (11 December 2008 to 31 March 2020). The present study indicates that sunspot number activity dominates in the southern hemisphere during the solar cycles 22 and 23, while during the solar cycle 24, the sunspot number becomes dominant in the northern hemisphere. It is also revealed that the magnitude of sunspot number activity for solar cycle 23 is more prominent in both the northern and southern hemispheres than in solar cycles 22 and 24. The power spectrum of daily sunspot numbers shows several significant periodicities in a wide range between 26 days and 83 days. We discuss the possible explanations of the observed periodicities and north-south asymmetry of the daily sunspot number in light of previous results and existing techniques.", "keyphrases": ["daily sunspot number", "n-s asymmetry", "periodicity"]}
{"id": "antonyuk2023asassn", "title": "ASASSN-19fy: Features of a Dwarf Nova in the \u201cPeriod Gap\u201d", "abstract": "Photometric studies of the dwarf nova ASASSN-19fy in the \u201cperiod gap\u201d were carried out in 2020-2021 over 24 nights at the Crimean Astrophysical Observatory of the Russian Academy of Sciences and 3 nights at the Sanglokh International Astronomical Observatory of the Institute of Astrophysics, National Academy of Sciences of Tajikistan. The observations covered a superoutburst, two successive rebrightenings, and a slow return to the pre-outburst (quiescent) state. During this time, superhumps were observed, in the evolution of which the stages of developed superhumps \u201cB,\u201d their damping \u201cC,\u201d and a transition between them were identified. The average period of the superhumps in stage \u201cB\u201d was 0.09278(13) days and it was found its increase during this stage at a rate of (dP / dT) / P = 10\u00b710\u20135. In stage \u201cC\u201d the period of the superhumps was equal to 0.092289(15) days. It is shown that ASASSN-19fy is the twelfth object to join the group of long-period dwarf novae similar to WZ Sge-type stars.", "keyphrases": ["asassn-19fy", "dwarf novae", "outbursts", "stars", "superhumps"]}
{"id": "grinin2023photometric", "title": "Photometric Activity of CQ Tau over a Time Interval of 125 Years", "abstract": "The star CQ Tau belongs to the family of UX Ori type stars and is characterized by very complicated photometric behavior and a complex structure of its circumstellar environment. Based on published photometric data, in this article we construct a light curve for this star covering 125 years. It implies that besides a random component characteristic of UX Ori type stars, the changes in brightness also include a large amplitude periodic component with a period of 10 years. It existence was suspected previously and new observations confirm its reality. This indicates the existence of a second component in the neighborhood of the star. Matter flows and density waves caused by the motion of the companion lead to periodic changes in the circumstellar extinction and brightness of the star. This result is discussed in the context of recent observations of CQ Tau with high angular resolution.", "keyphrases": ["periodic changes", "photometric activity", "ux ori type star"]}
{"id": "alaverdyan2022quark", "title": "Quark Matter in the NJL Model with a Vector Interaction and the Structure of Hybrid Stars", "abstract": "The properties of hadron-quark hybrid stars are studied when the quark phase is described in terms of a local SU(3) Nambu-Jona-Lasinio (NJL) model taking into account the contribution of the vector and axial-vector interaction between the quarks, and the hadronic phase, in the relativistic mean field (RMF) model. For different values of the vector coupling constant GV, the equations of state of the quark matter are calculated and the parameters of the hadron-quark phase transition are determined under the assumption that the phase transition takes place in accordance with Maxwell\u2019s construction. It is shown that for a larger vector coupling constant, the equation of state of the quark matter will be \u201cstiffer\u201d and the coexistence pressure P0 of the phases will be greater. Using the resulting hybrid equations of state, the TOV equations are integrated numerically and the mass and radius of the compact star are determined for different values of the central pressure Pc. It is shown that when GV is larger, the maximum mass of the compact star will be larger and thereby, the radius of the configuration with maximum mass will be smaller. Questions of the stability of hybrid stars are also discussed. It is shown that in terms of the model examined here, for all values of the vector coupling constant, a hybrid star with an infinitely small quark core is stable. These results are compared with recent measurements of the mass and radius of the pulsars PSR J0030+0451 and PSR J0740+6620, carried out at the International Space Station with the NICER X-ray telescope. A comparison of the theoretical results with observational data does not exclude the possibility of quark deconfinement in the interiors of compact stars.", "keyphrases": ["delta meson", "hadronic matter", "hybrid stars", "njl model", "quark matter", "quark phase transition", "relativistic mean field (rmf) theory", "vector interaction"]}
{"id": "chernov2022asynchronous", "title": "Asynchronous Rotation of a Massive Star in Close Binary Systems", "abstract": "The problem of asynchronous rotation of massive stars in close binary systems is investigated in this paper. A massive star with twice the sun\u2019s mass, a convective core, and an external radiative transfer zone (envelope) is examined. The model takes into account the influence of the companion on the star. It is assumed that the tidal flow is dissipated through radiative viscosity. The asynchrony of massive stars is explained by pseudosynchronization and differential rotation of the star.", "keyphrases": ["asynchronous stars", "close binary systems", "massive stars", "tidal interactions"]}
{"id": "saiyan2023theory1", "title": "Theory of Classical Gaseous Polytropes in an Integral Representation. II. Analytic Approximations to the Emden Functions and Density Profiles in a Closed Form", "abstract": "Analytic approximations are presented for the exact solutions of the Volterra type nonlinear integral equation of the second kind for classical gaseous polytropes in closed form. This equation is considered as the integral equivalent of the Lane-Emden differential equation with boundary conditions which describes the standard polytropic models in terms of a Cauchy problem. With the aid of a linear approximation of this equation and general heuristic considerations of a physical character, as well as with the aid of a graphical model and variation of the parameters of the approximating functions, approximate expressions for the Emden functions and the dimensionless density are obtained in closed form with a mean square accuracy from \u00a010-4 to a few percent for a series of values of the polytropic index n of practical interest (n = 0.5, 3, 4, 6, \u221e). Our previous approximation for the spatial density of the isothermal model is compared with a pseudo-isothermal law describing the distribution of the density of dark matter surrounding spiral galaxies and used by various authors for studying their rotation curves.", "keyphrases": ["emden function", "lane-emden equation", "polytropes", "volterra type nonlinear integral equation of the second kind"]}
{"id": "bharali2023modified", "title": "Modified Tsallis Holographic Dark Energy", "abstract": "In this work we propose Modified Tsallis Holographic Dark Energy (MTHDE) in General Relativity (GR) in the framework of Bianchi type III space-time. Einstein's field equations are solved by using a special law of variation of Hubble parameter H proposed by Berman which yields constant deceleration parameter (DP). Interestingly, for the two different constant values of deceleration parameter, we have obtained two different cosmological models. The model 1 behaves like a quintessence dark energy model whereas model 2 behaves like a cosmological constant model. A correspondence between model 1 and quintessence scalar field is established. The quintessence dynamics of the potential and scalar field are reconstructed which illustrates the accelerating phase of the Universe. Various parameters like deceleration parameter, Hubble parameter, anisotropy parameter, equation of state (EOS) parameter, etc. for both the cosmological models are thoroughly discussed. The results obtained are found to be consistent with the recent observations on the present-day Universe.", "keyphrases": ["deceleration parameter dp", "gr", "hubble parameter", "mthde"]}
{"id": "katore2023accelerating", "title": "Accelerating Kaluza-Klein Universe in Modified Theory of Gravitation", "abstract": "The purpose of this paper is to study the Kaluza-Klein universe in the context of the f (R, T) gravity theory using magnetized strange quark matter (MSQM). To obtain exact solutions of field equations, we assume two types of volumetric expansion: power law and exponential law volumetric expansions. The violation of energy conditions has been studied. The physical and geometrical properties of the examined model have also been investigated thoroughly.", "keyphrases": ["f(r", "t) gravity", "kaluza-klein metric", "magnetized strange quark matter", "power and exponential law"]}
{"id": "pawar2023bulk", "title": "Bulk Viscous String Cosmological Model with Power Law Volumetric Expansion in Teleparallel Gravity", "abstract": "In this paper, we have investigated the Bianchi-type V cosmological model which is spatially homogeneous and anisotropic in presence of bulk viscous fluid containing one-dimensional cosmic string. We have obtained the exact solutions of highly non-linear differential field equations considering the power-law volumetric expansion of the universe and f (T) = T formalism. Some physical and kinematical properties of the constructed model have been discussed and presented graphically and it is interesting to note that the resultant model resembles the recent observational data.", "keyphrases": ["bulk viscous fluid", "cosmic string", "teleparallel gravity"]}
{"id": "khurshudyan2023swampland", "title": "Swampland Criteria and Neutrino Generation in a Non-Cold Dark Matter Universe", "abstract": "In this paper, the implications of string Swampland criteria for a dark energy-dominated universe, where we have a deviation from the cold dark matter model, will be discussed. In particular, we have considered two models. One of them is one parameter model, while the second one has been crafted to reveal the dynamics in the deviation. The analysis has been obtained through the use of Gaussian processes (GPs) and H(z) expansion rate data (a 30-point sample deduced from a differential age method and a 10- point sample obtained from the radial BAO method). We learned that the tension with the Swampland criteria still will survive as in the cases of the models where dark matter is cold. In the analysis besides mentioned 40-point H(z) data, we used the latest values of H 0 reported by the Planck and Hubble missions to reveal possible solutions for the H 0 tension problem. Finally, the constraints on the neutrino generation number have been obtained revealing interesting results to be discussed yet. This and various related questions have been left to be discussed in forthcoming papers.", "keyphrases": ["gaussian processes", "non-cold dark matter model", "swampland criteria"]}
{"id": "israelyan2022multiwavelength", "title": "Multiwavelength Monitoring of Blazars PKS 2155-304 and S5 0716+71", "abstract": "The study of multiwavelength emission properties of blazar jets has the potential to shed light on the particle acceleration and emission mechanisms taking place in them. The emission of PKS 2155-304 (z = 0.116) and S5 0716+71 (z = 0.31) bright blazars in the optical/UV, X-ray and \u03b3 -ray bands is investigated by analyzing data from Fermi-LAT, Swift XRT and Swift UVOT telescopes. The multiwavelength light curves of both sources in these bands show multiple peaks when the flux increased substantially. In the optical/UV bands, the flux of both sources increased above 2\u221910-10 erg cm-2 s-1. The X-ray emission from PKS 2155-304 was characterized by a harder-when-brighter trend, whereas the \u03b3-ray emission from S5 0716+71 showed a moderated trend of softer-when-brighter. The correlation analysis shows a strong correlation between the UV and \u03b3-ray emission of PKS 2155-304, while there is a correlation between the optical/UV and X-ray emission of S5 0716+71. The observed broadband spectral energy distribution of both sources as well as the observed variability and correlations can be accounted for within one-zone synchrotron/synchrotron-self-Compton models.", "keyphrases": ["blazars", "pks 2155-304", "s5 0716+71", "x-rays", "\u03b3 \u2013rays"]}
{"id": "eftekhar2022wasp", "title": "WASP-18b Secondary Eclipses Revisited Using TESS Observation", "abstract": "We report the characterization of a transiting hot Jupiter WASP-18b at optical wavelengths measured by the transiting exoplanet survey satellite (TESS). We analyze the publicly available data collected by the TESS in sector 2. Here, we model the systematic noise using Gaussian processes (GPs) and fit it to the data using the Markov Chain Monte Carlo (MCMC) method. Modelling the TESS light curve returns a planet-to-star radius ratio, p=0.098010\u22120.000346+0.000368 and secondary eclipse depth of 354\u221210+11 part-per-million (ppm). The transit ephemeris of WASP-18b is updated using the MCMC method. Finally, we use updated ephemeris to look for transit time variations (TTVs) for WASP-18b to complement our study. We find a quite small deviation of transit timings from a linear ephemeris, which is statistically insignificant.", "keyphrases": ["data analysis", "individual", "methods", "photometric", "planetary systems", "stars", "techniques", "wasp-18"]}
{"id": "privatus2023revisited", "title": "The Revisited BPT Diagram from the Self-Consistent Analysis", "abstract": "Galaxies' spectral energy distribution has been explored through the use of spectral synthesis codes, and these techniques have been essential in identifying many aspects of the current galaxy evolution model. Most of the spectral synthesis codes that have been developed so far are solely stellar and assume a negligible nebular contribution to the overall continuum. FADO (Fitting Analysis using Differential Evolution Optimisation) is the first spectral synthesis code to fit self-consistently stellar and nebular components. Diagnostic diagrams are powerful tools for classifying galaxies based on the emission line ratio of collisionally excited lines such as [OIII] \u03bb 5007, [NII] \u03bb 6584, [SII] \u03bb 6716, 6731, [OI] \u03bb 6300, and the Balmer recombination lines such as H\u03b1, H\u03b2. This paper explores the impact of including nebular components on diagnostic diagrams. We investigated the results of the application of FADO to the Sloan Digital Sky Survey Data Release 8 using the data analysed by MPA-JHU, the Max Planck Institute for Astrophysics, and Johns Hopkins University. We found that in all diagnostic diagrams, the fluxes for FADO are higher than those for MPA-JHU; the difference is significant compared to the error in the flux measurement. FADO overestimates the flux ratio of all three diagnostic diagrams over MPA-JHU, but the overestimation is comparable with the line flux ratio errors. The results indicate that the inclusion of a nebular continuum is very important when fitting the spectral energy distribution as it increases the fluxes of all galaxies. However, there is a mild impact from the inclusion of nebular component analysis in the diagnostic diagrams used to classify the ionisation state of galaxies\u2019 interstellar medium.", "keyphrases": ["diagnostic diagram", "galaxies", "nebular"]}
{"id": "xin2022environmental", "title": "The Environmental Dependence of the Stellar Velocity Dispersion of Active Galactic Nucleus (AGN) Host Galaxies and Dependence of the Clustering Properties of AGN Host Galaxies on the Stellar Velocity Dispersion", "abstract": "We use two volume-limited active galactic nucleus (AGN) host galaxy samples constructed by Deng     Wen [47], and explore the environmental dependence of the stellar velocity dispersion in these two volume-limited AGN host galaxy samples. In the luminous volume-limited AGN host galaxy sample, the stellar velocity dispersion of AGN host galaxies apparently depends on local environments: AGN host galaxies with large stellar velocity dispersion exist preferentially in high density regime, while AGN host galaxies with small stellar velocity dispersion are located preferentially in low density regions. But in the faint volume-limited AGN host galaxy sample, this dependence is fairly weak. We also examine the dependence of the clustering properties of AGN host galaxies on the stellar velocity dispersion by cluster analysis, and find that in the luminous volume-limited AGN host galaxy sample, AGN host galaxies with small stellar velocity dispersion preferentially form isolated galaxies, close pairs and small groups, while AGN host galaxies with large stellar velocity dispersion preferentially inhabit the dense groups and clusters. In the faint volume-limited AGN host galaxy sample, although the fraction of isolated galaxies with small stellar velocity dispersion is apparently higher than the one with large stellar velocity dispersion, the trend in the luminous volume-limited sample is very difficultly observed. This likely is due to the galaxy number of the faint volume-limited AGN host galaxy sample being too small to ensure an ideal statistical analysis.", "keyphrases": ["cosmology", "fundamental parameters", "large-scale structure of universe \u2013 galaxies"]}
{"id": "savanov2023activity2", "title": "Activity of the Star Gl 414A with Two Planets and its Effect on the Loss of Mass of the Atmosphere of the Planet Gl 414A b", "abstract": "Results are presented from a study of manifestations of the activity of the dwarf Gl 414A of spectral class K7 with two planets, one of which (the planet Gl 414A b) with an eccentricity e=0.45 was found to be within the habitable zone over a large part of its orbit. Our analysis showed that the most reliable determination of the rotation period of Gl 414A was obtained from an analysis of photometric observations of the star in the KELT (Kilodegree Extremely Little Telescope) survey which yield a rotation period of P=42 days. However, the existence of this period is not confirmed by periodograms constructed from other observations of Gl 414A. The long-term activity cycle of the star is on the order of 3800 days (10.4 years). The obtained data on the activity of the star were used to estimate the loss of matter from the atmosphere of the planet Gl 414A b using an approximation formula for a model of atmospheric loss with a limit on energy. Based on 486 estimates of the parameter SHK, the loss of matter by the atmosphere of Gl 414A b over an interval of 5805 days (15.9 years) was calculated. The magnitude of these losses mainly lies within a range of log(Mloss) from 7.15 to 7.50 with a median of 7.30. For an eccentricity of 0.45 the distance from the central star to Gl 414A b ranges from 0.13 to 0.34 a.u., and for these distances the estimated losses of matter by the atmosphere are 16.21\u00b71017 and 2.37\u00b71017 g/s, respectively.", "keyphrases": ["activity", "atmospheres of exoplanets", "photometry", "planetary systems", "spots", "stars", "variability"]}
{"id": "nikoghossian2023evolution", "title": "Evolution of Spectrum Lines in an Inhomogeneous Atmosphere Illuminated by Nonstationary Energy Sources", "abstract": "The effect of the inhomogeneity of a scattering and absorbing medium of finite thickness on the evolution of spectrum lines which appear when it is illuminated by nonstationary energy sources is examined. Special attention is devoted to the role of scattering in the continuum spectrum. It is assumed that the inhomogeneity arises from the variation in the scattering coefficient with depth, which may be increasing or decreasing on approaching the illuminated boundary. Two types of nonstationarity of the external energy source are studied with a shape corresponding to \u03b4(t), the Dirac function, and H(t), the unit step function of Heaviside. The question of using observed time changes in the profiles of spectrum lines for determining their optical characteristics, the frequency dependence of the external energy sources, and the physical properties of the illuminated medium itself, is studied.", "keyphrases": ["cumulative distribution function", "evolution of spectrum line profiles", "inhomogeneous atmosphere", "probability density distribution"]}
{"id": "barsunova2022ux", "title": "UX OrI Type Stars in the Cluster IC 348: Results of Long-Term Photometric Monitoring", "abstract": "Results of a long-term (17 years) photometric monitoring of five T Tau stars in the VRI bands are presented. All the studied objects are members of the young cluster IC 348 and show the UX Ori type variability caused by changes in the circumstellar extinction. Three of them (V712 Per, V716 Per, and V909 Per) are classical T Tau type stars (CTTS) and the other two (V695 Per, V715 Per) are weak-line T Tauri stars (WTTS). Their light curves demonstrate the large diversity. Three of the objects have a combination of two different types of activity: stochastic UX Ori type variability and periodic brightness variations similar to those observed in AA Tau stars. Two of the stars demonstrate only the stochastic brightness variations owing to fluctuations in circumstellar extinction at different characteristic times. The features of the photometric activity of the stars investigated are discussed in detail in this article.", "keyphrases": ["ic 348", "photometry", "t tau type star", "ux ori"]}
{"id": "alenazi2023photometric", "title": "Photometric Study and Orbital Solution for Some Newly Discovered Eclipsing Binary Systems", "abstract": "We present an orbital solution and light curve analysis for the three newly discovered W UMa systems: V0757 And, IK Lyn, and V0996 Per by means of first CCD observations. New times of minima were estimated and the observed light curves were analyzed using the most recent version of Wilson-Devinney modeling code (WD code) based on model atmospheres by Kurucz. The accepted models revealed some parameters describing the orbit of each system which showed that the primary components in all systems are massive and hotter than the secondary components. The spectral types of the systems\u2019 components were adopted and the locations of the systems on the theoretical mass-luminosity and mass-radius relations revealed a good fit for all the systems components except the secondary components of the systems V0996 Per and V0757 And are located above the TAMS track.", "keyphrases": ["eclipsing binaries", "evolutionary state", "orbital solution"]}
{"id": "alam2023renyi", "title": "Renyi Holographic Dark Energy and Its Behaviour in f(G) Gravity", "abstract": "In this work, the Renyi holographic dark energy (RHDE) and its behaviour has been explored with the anisotropic and spatially homogeneous Bianchi type-I Universe in the framework of f (G) gravity. We use IR cutoff as the Hubble and Granda-Oliveros (GO) horizons. To find a consistent solutions of the field equations of the models, it is assumed that the deceleration parameter is defined in terms of function of Hubble parameter H. With reference to current cosmological data, the behaviors of the cosmological parameters relating to the dark energy model are evaluated and their physical significance is examined. It is observed that for both the models, the equation of state parameter approaches to -1 at late times. However, the RHDE model with the Hubble horizon exhibits stability from the squared sound speed, but the RHDE model with the GO horizon exhibits instability. In both the models, deceleration parameter and statefinder diagnostic confirm the accelerated expansion of the Universe and also correspond to the \u039bCDM model at late times.", "keyphrases": ["bianchi type-i metric", "cosmology", "f(g) gravity", "renyi holographic dark energy"]}
{"id": "audu2023unified", "title": "On the Unified Scheme of \u03b3-Ray Emitting Jetted Active Galactic Nuclei", "abstract": "The discovery of \u03b3 - ray emitting Seyfert galaxies has opened a new unified scheme of active galactic nuclei (AGN) in which jetted Seyfert galaxies are viewed as young counterparts of radio loud AGN. In this paper, we investigate the relationship between gamma-ray (\u03b3 - ray) properties of jetted Seyfert galaxies and those of traditionally radio galaxies, radio quasars and BL Lac objects. Results show that jetted Seyfert galaxies appear as low luminosity tail of the radio loud AGNs on the luminosity redshift (L\u03b3 \u2013 z) plane, indicating an evolutionary link between them. Nevertheless, narrow-line Seyfert galaxies (NLS1s) do not share similar characteristics with Seyfert galaxies as they possess higher luminosities and redshift than Seyfert galaxies, suggestive that NLS1s are more evolved sources. Analyses of \u03b3 \u2013 ray and radio core-dominance show that for each subclass of jetted AGN, the beaming angle is wider for radio than for \u03b3 - ray emissions. While Seyferts and radio galaxies, on average, have similar low inclination to the line of sight, NLS1 objects have orientations similar to quasars and BL Lacs. There is a significant correlation (r \u00a0 0.7) between the \u03b3 - ray core dominance and \u03b3 - ray luminosity. The results are consistent with the revised unification scheme and suggests that NLS1s are highly beamed sources whose parent populations can be found among the regular Seyferts and/or radio galaxies", "keyphrases": ["active galaxies", "galaxies", "gamma-rays", "jets", "seyferts"]}
{"id": "savanov2022activity", "title": "Activity of Stars with Planets in the Habitable Zone", "abstract": "Based on data on stars with planets located in the habitable zone, a study is made of manifestations of their activity. Light curves obtained during observations in the Q3 set with the Kepler Space Telescope for them were studied and the amplitudes of the brightness variability were studied in order to determine the presence and properties of spots on their surface. Estimates of the rotation periods of the objects were also obtained. Diagrams of the dependence of the area of the spots A on the surface of stars with exoplanets according to published data (including in those in the Habitable Zone) on the effective temperature and rotation period are examined. Indications are obtained that the distributions of the stars with exoplanets located in the habitability zone are shifted toward the region of lower spot areas and rotation periods compared to the data for all the stars with exoplanets. Data from the archive of the Kepler Space Telescope for a star with pronounced rotational modulation, KOI-3497 (Kepler-1512, KIC 8424002) are analyzed. It is noted that it should be characterized by a a star of spectral class K, rather than M. KOI-3497 has flare activity (47 flashes with energy E in the range from 2\u00b71031 to 2\u00b71032 erg have been recorded for it.)", "keyphrases": ["activity", "photometry", "planetary systems", "spots", "stars", "variability"]}
{"id": "sukharev2022study", "title": "Study of the Rapid Variability of the BL Lac Object MRK 421 in the Optical Range", "abstract": "MRK 421 is a giant elliptical galaxy in the Ursa Major constellation whose core has all the properties of a BL Lac object. It manifests a high activity and variability from the radio to gamma-ray ranges on time scales from a few hours to more than 10 years. MRK 421 has a large companion\u2014 a spiral, probably, also active galaxy (MRK 421-5). This paper presents the results of an analysis of observations (in the V, R, and I bands) as part of a joint Latvian-Ukrainian project for study of the variability of bright AGN. In addition, the light curves of MRK 421 from the AAVSO data base (American Association of Variable Star Observers) are analyzed to confirm the results of periodogram analysis. Ultimately, over the time interval studied here, MRK 421 is suspected of having a cyclical variability with a characteristic time in the range of 9.3-13.4 days determined by two different methods (approximation of the data by sinusoids and the CLEANest method), which is confirmed by an analysis of longer observations of MRK 421 in the V band (with AAVSO data). The longer variability of MRK 421 was also analyzed. It was found that in the V, R, and I light curves from AAVSO the maxima of the LS-periodograms correspond to periods of 1.6-1.7 years. This is close to earlier results from an analysis of historical light curves of MRK 421 obtained by other authors. The AAVSO data also indicate the presence in MRK 421 of a longer cycle of brightness variation with a characteristic time of 20-30 years.", "keyphrases": ["active galactic nuclei", "intra-day and extra-day variability", "mrk 421", "optical photometry", "radio galaxy"]}
{"id": "mirtadjieva2022instabilities", "title": "Instabilities of a Nonstationary Model of a Self-Gravitating Disk. V. New Annular Perturbation Modes", "abstract": "The problem of gravitational instabilities of annular perturbation modes against the background of a self-gravitating disk model nonlinearly oscillating in its plane, which is a nonstationary generalization of the well-known equilibrium Bisnovaty-Kogan-Zel\u2019dovich model is examined. The corresponding nonstationary analogs of the dispersion equation for the new annular perturbations are found. The results of the calculations are given in the form of critical dependences of the initial virial ratio on the degree of rotation of the disk. A comparative analysis is also made of the increments of the gravitational instability of these perturbation modes. It turns out that with an increasing degree of rotation of the nonstationary disk the range of the initial virial ratio for which annular structures can be formed increases.", "keyphrases": ["annular galaxies", "gravitational instability", "nonstationary model", "self-gravitating disk"]}
{"id": "khutsishvili2022variation", "title": "Variation of Doppler Velocities and D3 Spicule Half-Widths", "abstract": "This paper analyzes spectral observations of spicules in the helium D3 line obtained at the Abastumani Observatory (Georgia).with a 53-cm eclipse-free coronagraph. It is concluded that the changes in the Doppler (radial) velocities and half-widths of the D-3 lines are in antiphase. The maxima of the periods of the oscillations of the Doppler velocities coincide with the minima of the oscillations of the half-width of D3.", "keyphrases": ["d<sub>3</sub> line", "doppler velocities", "line half-half width"]}
{"id": "pawar2023plane", "title": "Plane Symmetric String Cosmological Model with Zero Mass Scalar Field in f (R) Gravity", "abstract": "In this article, an anisotropic Locally Rotationally Symmetric (LRS) Bianchi type I metric in the presence of cloud string fluid and zero mass scalar field in reference to f (R) gravity have been investigated. To obtain the deterministic solutions we assumed the weak field limit for a point-like source f (R) = R 3/2 and the very well-known expansion-shear scalar proportionality relation. Furthermore, some physical and kinematical parameters have been calculated to study the astrophysical consequences of obtained model, which shows a good resemblance to the recent observational data.", "keyphrases": ["bianchi type i metric", "cosmic string", "f (r) gravity", "scalar field"]}
{"id": "alenazi2022first", "title": "First Light Curve Modelling of Eclipsing Binary Systems V1264 Cas, V0664 Lac and GSC 0199-2035", "abstract": "Photometric analysis for the newly discovered systems V1264 Cas, V0664 Lac and GSC 0199-2035 were carried out using the most recent version of the Wilson-Devinney binary star modeling code (WD) based on model atmospheres by Kurucz. Accepted models revealed physical parameters use to adopt the spectral type of the components of the studied systems. Locations of the systems on the theoretical massluminosity and mass-radius relations revealed good fit for all the systems components except for the secondary components of the systems; V1264 Cas and GSC 0199-2035 where they lie above the TAMS track.", "keyphrases": ["eclipsing binaries", "evolutionary state", "light curve modelling"]}
{"id": "vasiliev2022emission", "title": "Emission Spectra of Galaxies with Supermassive Black Holes at z > 6", "abstract": "The masses of supermassive black holes and the (parent) galaxies containing them are related approximately by MBH \u00a0 0.002 M*. This indicates their close interaction during the process of their joint evolution. However, the large spread in the observed masses around this relation and, in particular, the considerably larger value, by an order of magnitude, of this mass ratio in the early universe (z > 6) observed in recent years indicates that the character of their interaction may vary significantly as they evolve. This circumstance requires a reliable observational determination of the ratios of the masses of the black holes, stellar populations, and interstellar gas in galaxies at large redshifts when these cannot be measured directly. In this paper a simple description illustrating this possibility is proposed. The features of the spectra of galaxies containing growing black holes and a forming stellar population are examined. A set of models with variations in the masses of the black hole, stellar population, and interstellar gas is used to illustrate the feasibility of finding the ratio of their masses using multiwavelength spectra: far infrared, submillimeter, and X-ray.", "keyphrases": ["extinction", "galaxies", "interstellar dust", "interstellar medium", "supermassive black holes"]}
{"id": "sharma2022transition", "title": "Transition 212-303 May Help for Detection of Methylene in a Cool Cosmic Object", "abstract": "Methylene is an important astrochemical compound. Though its laboratory spectrum was analyzed in 1982, its first unambiguous detection could be feasible after more than one decade in the hot core of Orion-KL nebula and the approximate molecular cloud of the continuum source W51M through its emission line 404-313. Since then waiting of its further detection has now broken as it has been detected in W51 E, W51 M, W51 N, W49 N, W43, W75 N, DR21, and S140 star forming regions, and in W3 IRS5 through the same transition 404-313. To find potential lines of methylene, we have performed Sobolev LVG analysis of each of the ortho and para species of methylene, considering 10 rotational levels having energy up to 324 cm-1. We have found only three lines, 404-313, 505-414 and 212-303 of methylene, which may help for its detection in a cosmic object. The line 212-303 lying at the lowest energy may be more helpful in a cosmic object having low kinetic temperature.", "keyphrases": ["ism", "methylene", "molecules", "radiative transition", "sobolev lvg analysis"]}
{"id": "nikhoghossian2022conservation", "title": "Conservation Laws in Time-Dependent Radiative Transfer Problems", "abstract": "The classical problem of radiative transfer with the escape of a photon from a semi-infinite scattering and absorbing atmosphere is generalized by the author to the case where the time expended by photons in multiple scattering in it is taken into account. The possibility of a variational formulation of the problem and the generalization of quadratic and bilinear conservation laws obtained in the stationary problem is raised. It is shown that the general statement of the problem does not allow this formulation owing to the nonpotentiality of the resulting differential operator; however, it is possible in the special case of conservative scattering. The resulting two conservation laws reflect the fact that the medium is homogeneous and time is isotropic.", "keyphrases": ["canonical equations", "conservation laws", "hamilton\u2019s principle", "time-dependent radiative transfer", "variational problem"]}
{"id": "nojiri2022new", "title": "New Entropies, Black Holes, and Holographic Dark Energy", "abstract": "The Bekenstein-Hawking entropy is a cornerstone of horizon thermodynamics but quantum effects correct it, while inequivalent entropies arise also in non-extensive thermodynamics. Reviewing our previous work, we advocate for a new entropy construct that comprises recent and older proposals and satisfies four minimal key properties. The new proposal is then applied to black holes and to holographic dark energy and shown to have the potential to cause early universe inflation or to alleviate the current Hubble tension. We then analyze black hole temperatures and masses consistent with alternative entropies.", "keyphrases": ["black holes", "entropy", "thermodynamics"]}
{"id": "abrahamyan2023optical", "title": "Optical Classification of BZG Objects from the BZCAT Blazar Catalog", "abstract": "In the blazar catalog BZCAT the objects are divided into 4 types: BZB, BZQ, BZG, and BZU. In this paper BZG objects are studied in order to determine their physical nature. Of the 274 BZG objects, 150 have optical spectra in the SDSS spectroscopic catalog, for which a detailed spectral classification has been carried out. A radio study showed that these objects mostly (69", "keyphrases": ["blazar", "optical spectral classification", "quasar", "radio spectral index"]}
{"id": "movsessian2022hh", "title": "HH 1216: The Extended Bipolar Flow Associated with IRAS 06212-1049", "abstract": "A narrow-band survey of star-formation regions is under way with the 1-m Schmidt telescope at the Byurakan Observatory (the Byurakan Narrow Band Imaging Survey, BNBIS). One of the goals of the survey is a search for Herbig-Haro (HH) type outflows in the neighborhoods of bright infrared sources in dark clouds. One of the first discoveries in this program was an extended bipolar outflow from the optically invisible IRAS 06212-1049 source associated with a previously unknown biconical reflecting nebula. This bipolar outflow (HH 1216) consist of several optically bright HH-knots and a small emission jet along the axis of the nebula. The overall length of the observable part of the HH 1216 outflow is estimated at about 1 pc and its distance at \u00a0950 pc. The bolometric luminosity of the source IRAS 06212-1049 is at least 13 L\u2a00. Yet another HH-knot, HH 1217, has been observed near the source IRAS 06216-1044 with a luminosity of at least 13 L\u2a00 and located in the same dark cloud. Yet another isolated emission object has been found in this region; it is probably a distant planetary nebula.", "keyphrases": ["dark clouds", "herbig-haro outflows and objects", "ir sources", "pms-stars"]}
{"id": "saiyan2023theory2", "title": "Theory of Classical Gaseous Polytropes in an Integral Representation. I. Some General Results", "abstract": "The well known results of the theory of classical gaseous polytropes are presented in the framework of an integral approach where the standard Lane-Emden differential equation for a spherically symmetric gravitating mass is examined via its equivalent in the form of a nonlinear integral Volterra equation of the 2nd kind. It is shown that the inverse Laplace transform of the Lane-Emden equation for polytropes with an index of n=5 (Schuster model) is a recurrence relation for Bessel functions of the first kind. The invariance of the nonlinear integral Volterra equation with respect to homological transformations is shown, as well as the possibility of obtaining singular solutions under certain conditions. It is also shown that for whole integral and half integral polytrope indices, this equation is equivalent to a multidimensional integral equation, and finding the expansion of the Emden function in a power series of the dimensionless distance \u03be from the center of the polytrope is equivalent to finding the Neumann series and the iterated nuclei in the Fredholm theory. Approximations of the Emden functions in closed form and their applicability to various astrophysical objects will be presented and discussed in the second part of this paper. Polytropes of other geometries and dimensionalities are not considered here.", "keyphrases": ["emden function", "lane-emden equation", "nonlinear volterra-type integral equation of the second kind", "polytropes"]}
{"id": "glagolevskij2023features", "title": "Features of the Magnetic Field Behavior of the Ae/Be Star HD190073", "abstract": "An attempt is made to explain the sudden change in the surface structure of the magnetic field of the type HAe/Be star HD190073 assuming a variable nonstationarity of the upper layers of the star which takes place owing to accretion and burning of deuterium. At the same time, data are presented which contradict the assumption of magnetic field generation within the convective core.", "keyphrases": ["ae/be stars", "hd190073", "magnetic field"]}
{"id": "savanov2022spottedness1", "title": "Spottedness Activity of the Young Star TOI 1227 with a Planetary System from Lower Centaurus Crux OB Association (Musca)", "abstract": "Based on high-precision data from the archive of the TESS space mission, a study of the photometric variability of the brightness of TOI 1227, a young member of the Musca group with an age of 11 million years. is carried out. The obtained results are compared with data on another young star with an exoplanet that we studied previously, EPIC 205117205 (K2-33) from the Upper Scorpius subgroup of the Sco-Cen association. TOI 1227 and K2-33 are among the youngest of the stars with planetary systems studied using data from the Kepler and TESS missions. Estimates of its rotation period and the amplitude of its brightness amplitude are made from all the accessible observations, and the standard method is used to estimate the absolute measure of the spottedness parameter A. The area of the spots on the surface of TOI 1227 is 14600 MSH and significantly exceeds the area of the spots on the sun. It is found that for TOI 1227 over the observation interval in three sectors from the TESS space mission, there were no manifestations of flare activity. Besides its youth, the TOI 1277 system is of special interest owing to the substantially larger radius of the planet found compared to other planets with low-mass stars. New observations and further studies will be required in order to refine the properties of TOI 1227b and the reliability of its detection.", "keyphrases": ["activity", "photometry", "planetary systems", "spots", "stars", "variability"]}
{"id": "movsessian2023herbig", "title": "Herbig-Haro Flows and Young Stars in the Dobashi 5006 Dark Cloud", "abstract": "Two new Herbig-Haro flows were found in a study of the isolated Dobashi 5006 dark cloud (l = 216\u00b0.7, b = \u201313\u00b0.9): one certain (HH 1179) and one presumable, associated with the infrared sources 2MASS 06082284-0936139 and 2MASS 06081525-0933490, correspondingly. Judging from their spectral energy distributions, these sources may be Class 1 objects with luminosities of order 23 L\u2a00 and 3.6 L\u2a00, respectively. They are part of the poor star cluster MWSC 0739, study of which based on data from the Gaia DR3 survey has made it possible to detect 17 stars which are probably members of it. A list of them and their main parameters is given. The distance of the cluster is estimated to be 820 pc and the color excess on the path to the cluster is E(BP - RP) \u2248 1.05 mag. All of these stars are PMS-objects and most of them are optically variable. It is concluded that the newly discovered compact star-formation zone in the Dobashi 5006 cloud has an age of no more than a few million years and this process continues up to the present time.", "keyphrases": ["dobashi 5006", "herbig-haro objects", "young stars"]}
{"id": "zhao2023effect", "title": "Effect of the Interaction Between Hyperons on the Moment of Inertia of the Proto Neutron Stars", "abstract": "Effect of the interaction between hyperons on the moment of inertia of proto neutron stars (PNSs) PSR J0740+6620, PSR J0348+0432, PSR J1614-2230 and PSR J0737-3039A is examined by means of relativistic mean field theory. Taking into account the interaction between hyperons, the mass M of the PNS decreases with respect to the same radius R, the energy density \u03b5 increases with respect to the same pressure p, and the moment of inertia I of the PNS decreases with respect to the same central energy density \u03b5c. Under the constraint of the mass of the PNS, considering the interaction between hyperons, the larger the mass of the PNS, the more the radius and moment of inertia of the PNS decrease, while the more energy density and pressure increase. For smaller PNSs, the effect can be negligible.", "keyphrases": ["hyperon", "neutron star", "relativistic mean field theory"]}
{"id": "abdel_sabour2022photometric", "title": "Photometric and Spectroscopic Analysis of the SX Phe Star BL Cam", "abstract": "In the present paper, we report the photometric and spectroscopic observations of the pulsating star BL Cam obtained by the 1.88 m telescope at the Kottamia astronomical observatory (KAO). Fourier analysis of the light curves indicates one frequency, 25.14427 c/d, with harmonics 51.112 c/d, 33.388 c/d, and 17.72464 c/d. The frequency of 31-32 c/d reported in the literature is not detected in our data except for one close to 33.3882934 c/d. A total of 55 new times of maximum light have been presented. A new value of (1/P) dP/dt is estimated using the O-C diagram based on all newly obtained times of maximum light combined with those taken from the literature, assuming the periods are decreasing and changing smoothly. Using model atmosphere analysis, we computed the effective temperature and surface gravity as Teff = 7625 \u00b1 300 K and logg = 4.30 \u00b1 0.37. The bolometric magnitude Mbol = 2.335, radius R = 1.69 R\u2a00, luminosity L = 0.957 L\u2a00, the mass M = 1.68M\u2a00, and pulsation constant Q = 0.025 days. Locations of the star on the M-R and M-L diagrams indicate that it is close to the ZAMS track and is an unevolved star.", "keyphrases": ["frequency and pulsation analysis", "model atmosphere analysis", "stars", "sx phe stars", "variables"]}
{"id": "lyubimkov2022red", "title": "The Red Giants EK Eri and OU And as Probable Descendents of Ap-stars: A Search for Abundance Anomalies", "abstract": "The red giants EK Eri and OU And, with magnetic fields Bmax=99 and 41 G, respectively, which presumably are descendents of magnetic Ap-stars, are studied. Their fundamental parameters are found and their chemical composition is analyzed. The abundances of 17 elements from lithium (Z=3) to hafnium (Z=72) are found for these giants, as well as for the comparison star \u03b2Gem (Pollux). The abundance of nitrogen and the carbon isotope ratio 12C/13C are found using CN molecular lines. The low ratios 12C/13C=17.3 for EK Eri and 17.2 for \u03b2Gem prove that these giants have passed through deep convective mixing in the First Dredge-Up (FDU) phase. For OU And, it was not possible to determine 12C/13C because of the relatively fast rotation and higher effective temperature of this star. but a high ratio N/C (higher than the sun by 1.1 dex) may serve to confirm that even this giant has also passed through an FDU phase. An analysis of the chemical composition led to an important conclusion: none of the three giants have any kinds of anomalies in the abundances of the heavy elements; in particular there are no excesses of any kind in the abundances of the rare-earth elements, which reach 4 dex in magnetic Ap-stars. The absence of such excesses may be a consequence of deep mixing during the FDU phase. In all three cases the abundances of carbon and nitrogen revealed the expected anomalies for stars of this type: a deficit of C from -0.3 to -0.6 dex and an excess of N from +0.3 to +0.6 dex. The theoretical prediction of a constant sum of C+N+O in the evolution process is confirmed: the combined abundance log\u03b5(C+N+O)=8.96-8.98 essentially coincides with the initial value of this quantity, specifically with the value of log\u03b5(C+N+O)=8.94 obtained for the sun and for early B-type MS stars. The Li 6707.76 \u00c5 line was detected in the spectra of all three stars, revealing a lithium abundance of log\u03b5(Li)=0.7-1.5; however, the presence of lithium in the atmospheres of giants that have passed through an FDU phase conflicts with the standard theory. Two of the observed phenomena that were unexpected for post-FDU giants, i.e., the existence of a magnetic field and the presence of lithium in the atmosphere, can be explained in terms of a single hypothesis: engulfment by a red giant of a planet with a mass several times that of Jupiter.", "keyphrases": ["chemical composition", "evolution", "red giants"]}
{"id": "deng2023environmental", "title": "Environmental Dependence of Different Colors of Active Galactic Nucleus (AGN) Host Galaxies", "abstract": "Using the apparent-magnitude limited active galactic nucleus (AGN) host galaxy sample of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12), we investigate the environmental dependence of the u-r, u-g, g-r, r-i and i-z colors of AGN host galaxies. We divide the whole apparent-magnitude limited AGN sample into many subsamples with a redshift binning size of \u2206z = 0.01, and analyze the environmental dependence of all five galaxy colors of subsamples in each redshift bin. It turns out that overall, all five galaxy colors of AGN host galaxies are weakly correlated with the local environment.", "keyphrases": ["fundamental parameters - galaxies", "galaxies", "statistics"]}
{"id": "denissyuk2022results", "title": "Results of Spectral Observations of 15 Seyfert Galaxies", "abstract": "Results of spectral studies of fifteen Seyfert galaxies at red wavelengths based on long-term observations are presented. In this range there are lines of hydrogen H\u03b1, [NII], [OI], and [SII]. Data on the absolute emission fluxes in the emission lines and in the continuum at the wavelength of \u03bb = 6400 \u00c5 are presented. In order to objectively compare the examined galaxies with one another, the values of their luminosities were calculated in absolute units with the distances to these objects taken into account.", "keyphrases": ["emission fluxes", "emission lines", "galaxies with active nuclei", "seyfert galaxies"]}
{"id": "lyubimkov2022nine", "title": "Nine Nearby K-Giants with Planets: A Detailed Analysis of their Chemical Composition", "abstract": "The chemical composition of 9 K-giants with planets located within 100 pc of the sun is studied. Here fundamental parameters of the stars which we have found previously are used; for the giant \u03bc Leo the metallicity index [Fe/H] = +0.26 is redetermined along with the microturbulence parameter Vt=1.3 km/s from the lines of FeI. The abundances of 17 chemical elements from lithium (Z = 3) to hafnium (Z = 72) are found. Some elements are analyzed without assuming LTE (local thermodynamic equilibrium). Infrared CN molecular lines are used to determine the nitrogen abundance and the carbon isotope ratio 12C/13C. Low values of 12C/13C=8-18 show that the program giants have passed through deep convective mixing in the FDU (First Dredge-Up) phase. When analyzing the abundances obtained we added our recent data for the magnetic giants EK Eri and OU And found by the same technique. Lithium was not found for 7 of the 11 giants in question. An absence of lithium in atmospheres of stars that have passed through deep mixing in the FDU phase agrees with theoretical predictions. However for 4 of the giants, we found lithium; earlier for 3 of these 4 stars a magnetic field has been detected. These two phenomena, i.e., the presence of lithium in its atmosphere and the existence of a magnetic field, are unexpected for post-FDU giants in terms of the standard theory, can be be explained in the framework of a single hypothesis: an engulfment by a star of the planet with a mass several times that of Jupiter. For the 11 giants examined here we found a distinct correlation between the [N/C] and [N/O] values. A comparison of the observed relation with the theoretical model computed with rotation included showed that the theory cannot explain the high values of [N/C]=1.0 \u2013 1.4 obtained for the most of the giants. Apparently, the known hypothesis of extra mixing is needed here. The combined abundance of C+N+O, which, according to the theory, should remain constant from the star\u2019s formation, showed a correlation with the metallicity index [Fe/H]. In this regard, for the stars with the normal metallicity [Fe/H] = \u00b10.1 a value of log\u03b5(C + N + O) = 8.97 was found that agrees perfectly with the solar value log\u03b5(C + N + O) = 8.94. For the giant m Leo with a high metallicity [Fe/H]=+0.26 the highest value of log\u03b5(C + N + O) = 9.31 was obtained. An anticorrelation was found between [RE/Fe], the mean abundance of rare earth (RE) elements (relative to Fe) and the index [Fe/H]. It is in good agreement with data for F- and G-dwarfs in the sun\u2019s neighborhood and reflects the initial chemical composition of the giants studied here.", "keyphrases": ["chemical composition", "exoplanets", "red giants"]}
{"id": "fursyak2023large", "title": "Large-Scale Electric Currents in Coronal Heating Processes above Active Regions on the Sun", "abstract": "This paper poses the problem of studying the role of large-scale electric currents propagating in the upper layers of the solar atmosphere in processes of coronal heating of the sun. For detecting and calculating the magnitude of the large-scale electric current, data on the distribution of the components of the magnetic field vector in the photosphere provided by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) were used. Photoheliograms of the sun\u2019s corona in the ultraviolet radiation channels at 131, 171, 193, and 211 \u00c5 provided by the Atmospheric Imaging Assembly (AIA/SDO) were used to estimate the temperature in the corona above active regions (ARs). The dynamics of the large-scale current and the average temperature in 9 regions with different levels of flare activity of the corona above the ARs have been studied and charts of the spatial distribution of the temperature in the corona above the ARs have been constructed. The following results have been obtained: 1. Heating of the coronal matter owing to ohmic dissipation of large-scale electric currents proceeds in a stationary regime. 2. The increase in the average temperature in the corona above an AR during solar flares to < log T\u00af > = 6.3 - 6.5 (2.0-3.2 MK) is caused, not only by heating of coronal structures by large-scale electric currents, but also by other processes at coronal elevations. 3. For the NOAA 11899 and 12494 regions a reduction in the average temperature of the corona to < log T\u00af > = 5.7 (0.5-0.6 MK) was observed with a simultaneous drop in the values of the large-scale electric current to zero. These observations indicate that the mechanism for heating of the corona by ohmic dissipation of electric currents is shut off at zero values (within the computational errors) of the large-scale electric current. 4. In the NOAA regions 12192 and 12371, when constructing charts of the temperature distribution in the corona outside flare events, hot structures with temperatures \u2265 10 MK were observed outside the flare events which appear to mark the location of the channel of a large-scale electric current at coronal elevations. For the NOAA region 12192 this assumption is confirmed by a numerical simulation carried out in 2016.", "keyphrases": ["active regions", "coronal heating", "electric currents", "magnetic field", "sun", "ultraviolet radiation"]}
{"id": "avagyan2023motion", "title": "Motion of a Particle in the Field of an Infinite Flat Slab", "abstract": "This paper studies the motion of a light signal and a test particle in the field of an infinite flat slab in terms of the general theory of relativity. The two cases of an external solution for a gravitational field in a vacuum corresponding to Rindler and Taub metrics are examined. The time of the motion and the path traveled by a particle before it stops are determined. It is shown that in the Taub geometry, as opposed to a light signal, a material particle does not reach a singularity. The minimum distance from the singularity is determined as a function of the particle energy. Results in terms of the special theory of relativity are given for comparison.", "keyphrases": ["plane-symmetric gravitational field", "rindler metric", "taub metric"]}
{"id": "harutyunyan2023multiwavelength", "title": "Multiwavelength Properties of Selected High Redshift Blazars", "abstract": "High-redshift blazars detected in the \u03b3 -ray band are the most powerful steady objects in the universe. Multiwavelength observations of these distant objects are of particular interest as they can help to understand the \u03b3 -ray evolution of blazars as well as the formation and propagation of relativistic jets in the early epochs of the Universe. In this study, we investigate the origin of broadband emission from 7 blazars with redshifts greater than 2.5 by analyzing the data accumulated with Swift UVOT/XRT and Fermi-LAT. We observe several flaring periods with significant increases in flux and hardening of the photon index in the high-energy \u03b3 -ray band for PKS 1830-211 (z = 2.507), LQAC 247-061 (z = 2.578), TXS 0536+145 (z = 2.690), and 4C+41.32 (z = 2.550). PKS 1830-211 was in an extraordinarily bright state on MJD 58596.49 when the 3-day averaged flux increased up to (1.74 \u00b1 0.04)\u00b710\u20135 photon cm-2 s-1. The X-ray emission of PKS 1830-211 is also strongly variable and is characterized by a hard photon index in the range of 0.34-0.94. To model the time-averaged broadband spectral energy distribution of the considered sources, we used a one-zone leptonic emission mechanism for the inverse Compton scattering, considering both synchrotron and external photons. We estimated the corresponding parameters of the emitting particles as well as the energetics of the jet.", "keyphrases": ["blazars", "gamma-rays", "non-thermal", "radiation mechanisms", "x-rays"]}
{"id": "kondratyev2022halo", "title": "Halo Effect on Bar Rotation in Galaxies", "abstract": "The effect of a massive gravitating halo on the rotation of an ellipsoidal bar in disk galaxies is studied. The method is based on calculating the moment of forces between a bar and a halo using a function of their mutual gravitational energy. Two models are examined to test the new method: a simple variant with uniform components and a more complex variant in which the halo is represented by a layered-heterogeneous ellipsoid with a parabolic density law. For both models expressions are obtained for the mutual gravitational energy of the bar and the halo, the Lagrangian is constructed, and differential equations for the nonlinear rotational oscillations of the bar are derived. These equations describe the rotation of a bar with a variable angular velocity. The frequencies and periods of the librations of the angular velocity of the bar are found both in the general nonlinear case and in the approximation of harmonic oscillations. It is found that taking the inhomogeneity of the halo into account can significantly (by roughly a factor of 2) increase the period of these oscillations.", "keyphrases": ["bars and halos", "frequencies and periods of oscillations", "linear and nonlinear equations of rotational oscillations of bars", "mutual energy of ellipsoids", "structure of disk galaxies"]}
{"id": "kryzhanovsky2023surface", "title": "Surface Photometry of 50 Dwarf Galaxies in the Local Volume", "abstract": "Results of surface photometry of 50 galaxies in the Local Volume based on archived images obtained with the Hubble Space Telescope are presented. Integrated magnitudes in the V and I bands are introduced for the chosen galaxies, along with brightness and color profiles. The obtained photometric parameters are compared with the measurements of other authors.", "keyphrases": ["dwarf galaxies", "galaxies", "photometric parameters- galaxies"]}
{"id": "savanov2022spottedness2", "title": "Spottedness Activity of the Young Star HIP 94235 from the Moving Group AB Doradus", "abstract": "Based on high-precision data from the archive of the TESS space mission, a study is made of the photometric variability of the brightness of HIP 94235, a bright star belonging to the 120 million years old moving group AB Doradus. We obtained an estimate for the rotation period of the star and the amplitude of the brightness variability, as well as an estimate of 31750 m.s.h. for the spottedness parameter A in an absolute measure, substantially greater than the density of spots on the Sun. During the interval of the observations with the TESS space mission there were no manifestations of flare activity on HIP 94235, For each sector of the observations which sequentially cover one period of the star\u2019s rotation, the inverse problem of recovering maps of the surface temperature inhomogeneities of the star from the light curve was solved for the position of the active regions and to study their time evolution. The differential rotation parameter of the star \u2206\u03a9 =0.038 \u00b1 0.07 rad/d is estimated from the relative differences in the displacements of the active regions. The results are compared with data on another young solar-type star with an exoplanet which we have studied, TOI 837, a member of the southern cluster IC 2602 with an age of 35 million years.", "keyphrases": ["activity", "photometry", "planetary systems", "spot", "stars", "variability"]}
{"id": "kholtygin2023ultrafast", "title": "Ultrafast Variability of Line Profiles in Spectra of \u03b3 Ori", "abstract": "High time-resolution (\u2206T\u00a02 min) observations of the B2V star \u03b3 Ori on the 2-m telescope at the Terskol Peak Observatory are presented. Regular components of line profile variations with periods from \u00a057 min to \u00a0130 min are recorded. The nature of these variations is discussed.", "keyphrases": ["individual", "spectra \u2014 line profiles\u2014 variability", "stars", "\u03b3 ori"]}
{"id": "andreasyan2023possible", "title": "On a Possible Mechanism for the Start or Resumption of Activity of Radio Galaxies in Clusters of Galaxies", "abstract": "We study the close proximity of the well-known and well-studied 3C31 class FRI radio galaxy in order to reveal the influence of the environment on an extragalactic radio source. It was shown that about 110 million years ago the galaxies NGC 380 and NGC 386 were located near the galaxy NGC 383 (the parent galaxy of 3C31). On the other hand, the modeling of the spectral characteristics of the radio emission of the central part of the radio galaxy 3C31 gives an estimate of the age of the central jet of about 100 million years. Therefore, it can be assumed that one of the possible reasons for the appearance or resumption of the radioactivity of the galaxy NGC 383 may be a triple close passage of galaxies.", "keyphrases": ["clusters of galaxies", "environment of galaxies", "galaxies", "radio galaxies"]}