MICROLENSING OF OPTICALLY THIN CLOUDS IN ACTIVE GALACTIC NUCLEI

We construct models of active galactic nuclei consisting of an accreti on disk and a region filled with optically thin cloudlets reprocessing a part of X-ray radiation into lower frequencies. We fit our model pa rameters to Q2237+0305 - a rapidly variable quasar, whose luminosity c hanges are attributed to microlensing. We simulate the microlensing li ght curves for our model and compare the rate of luminosity changes wi th the observations. We also compare the results with the results obta ined for other accretion disks models of the source. Our two-component model of the source is better than the other examined models in repro ducing simultaneously the rapid variability and the spectrum of the so urce, but the difference is not dramatic. Our model is not ruled out b y the observations of Q2237+0305 summarized by Racine (1992). If the o bservations of Pen et al. (1994) are confirmed, all the source models including accretion disks are in trouble.