Microlensing of Lensed Supernovae

Given the number of recently discovered galaxy-galaxy lens systems, weanticipate that a gravitationally lensed supernova will be observed within thenext few years. We explore the possibility that stars in the lens galaxy willproduce observable microlensing fluctuations in lensed supernova light curves.For typical parameters, we predict that ~70% of lensed SNe will showmicrolensing fluctuations > 0.5 mag, while ~25% will have fluctuations > 1 mag.Thus microlensing of lensed supernova will be both ubiquitous and observable.Additionally, we show that microlensing fluctuations will complicatemeasurements of time delays from multiply imaged supernovae: time delaysaccurate to better than a few days will be difficult to obtain. We alsoconsider prospects for extracting the lens galaxy's stellar mass fraction andmass function from microlensing fluctuations via a new statistical measure, thetime-weighted light curve derivative.Comment: 13 pages, emulateapj format; accepted in ApJ; expanded discussion of time delay uncertaintie