MICROLENSED LIGHT CURVES FOR THIN ACCRETION DISKS AROUND SCHWARZSCHILD AND KERR BLACK-HOLES

We present surface brightness maps for thin accretion disks around Schwarzschild and Kerr black holes. These disks are a few times smaller than those used by Rauch and Blandford, and some of our models are slightly less luminous than theirs. Examples of microlensed light curves are calculated by convolving these accretion disk maps with the magnification patterns obtained from microlensing calculations. The light curves exhibit event-like variations with amplitudes and time scales comparable to those observed in QSO 2237 + 0305. We conclude that thin thermal accretion disk models are not in contradiction with the observed microlens-induced variations of QSO 2237 + 0305. Current and future monitoring programs of QSO 2237 + 0305 with accurate color measurements will decide empirically about the viability of our model: it predicts color changes correlated with the maxima in the microlensed light curves.