iPTF16geu: A multiply imaged, gravitationally lensed type Ia supernova

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Science  21 Apr 2017:
Vol. 356, Issue 6335, pp. 291-295
DOI: 10.1126/science.aal2729

Multiple images of a type Ia supernova

General relativity indicates that any sufficiently massive object bends the path of light passing by it. This effect is known as gravitational lensing. Goobar et al. have identified a supernova that is strongly lensed by a foreground galaxy, causing it to be highly magnified and splitting the light into four separate images. What is more, it is a type Ia supernova, a well-studied variety with reliable properties that can be used to constrain models of the lensing. This distinctive object will enable cosmological measurements and can be used to probe the distribution of mass in the foreground galaxy.

Science, this issue p. 291


We report the discovery of a multiply imaged, gravitationally lensed type Ia supernova, iPTF16geu (SN 2016geu), at redshift z = 0.409. 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. We used high-spatial-resolution observations to resolve four images of the lensed supernova, approximately 0.3 arc seconds from the center of the foreground 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. The relative magnifications of the four images provide evidence for substructures in the lensing galaxy.

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