News Finding: Because of the standard candle nature of iPTF16geu, this is the first time this measurement could be made without any prior assumptions about the form of the lens or cosmological parameters.
Paper Finding: The observations probe a physical scale of~1 kiloparsec, smaller than is typical in other studies of extragalactic gravitational lensing.
News Context: Using the data gathered, the team calculated the magnification power of the lens to be a factor of 52. Because of the standard candle nature of iPTF16geu, this is the first time this measurement could be made without any prior assumptions about the form of the lens or cosmological parameters. Not only does their discovery rely on a very particular and precise alignment of objects in the sky, but they are also only visible for a short time.
Paper Context: This phenomenon was identified because the light from the stellar explosion was magnified more than 50 times by the curvature of space around matter in an intervening galaxy. The observations probe a physical scale of~1 kiloparsec, smaller than is typical in other studies of extragalactic gravitational lensing. The large magnification and symmetric image configuration imply close alignment between the lines of sight to the supernova and to the lens.