MICROLENSING OF OPTICALLY THIN CLOUDS IN ACTIVE GALACTIC NUCLEI

We construct models of active galactic nuclei consisting of an accretion disk and a region filled with optically thin cloudlets reprocessing a part of X-ray radiation into lower frequencies. We fit our model parameters to Q2237+0305 - a rapidly variable quasar, whose luminosity changes are attributed to microlensing. We simulate the microlensing light curves for our model and compare the rate of luminosity changes with the observations. We also compare the results with the results obtained for other accretion disks models of the source. Our two-component model of the source is better than the other examined models in reproducing simultaneously the rapid variability and the spectrum of the source, but the difference is not dramatic. Our model is not ruled out by the observations of Q2237+0305 summarized by Racine (1992). If the observations of Pen et al. (1994) are confirmed, all the source models including accretion disks are in trouble.