Generation of X-ray emission in the vicinity of Kerr black holes

We study spectra arising from Comptonization taking place close to a Kerr black hole horizon. We find that the spectra strongly depend on the inclination of the line of sight, with larger inclinations corresponding to harder spectra. We indicate that such anisotropy could be responsible for properties of the X-ray spectra of Seyfert galaxies, which appear to be intrinsically harder in type 2 objects than in type 1. We find also that a model involving irradiation of a cold disk surface by X-rays from a central hot corona in the Kerr geometry can explain properties of reflection features observed in MCG--6-30-15.