Seeing double: Strong gravitational lensing of high-redshift supernovae

With the advent of large, deep surveys, the observation of a strongly gravi tationally lensed supernova becomes increasingly likely. High-redshift surv eys continue apace, with a handful of Type Ia supernovae observed to date a t redshifts of 1 or greater. In addition, a satellite has been proposed (th e 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 e xceedingly unlikely that we will see a multiply imaged supernova from ongoi ng 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, i mage separations, and relative image magnifications, and the SNAP strong-le nsing database will offer measures of Omega (m), Omega (Lambda), and H-0, i ndependent of SNAP's primary goal of establishing the distance-redshift rel ation. 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 me asurements.