Seeing Double: Strong Gravitational Lensing of High-Redshift Supernovae

Abstract

With the advent of large, deep surveys, the observation of a strongly gravitationally lensed supernova becomes increasingly likely. High-redshift surveys continue apace, with a handful of Type Ia supernovae observed to date at redshifts of 1 or greater. In addition, a satellite has been proposed (the Supernova/Acceleration Probe [ SNAP ]) that will be dedicated to observing thousands of supernovae per year out to a redshift of 1.7. Although it is exceedingly unlikely that we will see a multiply imaged supernova from ongoing surveys, we find that SNAP would observe at least eight such events per year. Since having a standard candle is inessential to most lensing studies, SNAP 's large sample of Type II supernovae contributes to this rate. Each case of strong lensing allows for a precise determination of time delays, image separations, and relative image magnifications, and the SNAP strong-lensing database will offer measures of Ω m , Ω Λ , and H 0 , independent of SNAP 's primary goal of establishing the distance-redshift relation. These systems also constrain models for the matter density profiles of galaxies and clusters. Furthermore, lensed Type Ia supernovae afford us the opportunity to break the mass-sheet degeneracy found in many lensing measurements.