X-Ray Spectra from Two-Phase Accretion Disks

A model for the X-ray emission from radio-quiet active galactic nuclei (AGNs) is considered. The X-rays are produced via inverse Compton (IC) emission in a hot corona embedding a colder accretion disk. Soft thermal photons emitted by the cold layer provide the main source of cooling for the hot electrons in the corona. At the same time, about half of the high-energy photons produced in the corona are effective in heating the underlying dense layers. The local viscous dissipation within the disk is considered negligible. The energy coupling between the disk and the corona forces the electron temperature to adjust so as to maintain comparable luminosities in the soft and hard components of the emitted radiation, independently of the optical depth of the scattering medium