Anisotropic illumination of AGN’s accretion disk by a non thermal source I. General theory and application to the Newtonian geometry

We present a model of accretion disk where the disk luminosity is entirely due to the reprocessing of hard radiation impinging on the disk. The hard radiation itself is emitted by a hot point source above the disk, that could be physically realized by a strong shock terminating an aborted jet. This hot source contains ultrarelativistic leptons scattering the disk soft photons by Inverse Compton (IC) process. Using a simple formula to describe the IC process in an anisotropic photon field, we derive a self-consistent angular distribution of soft and hard radiation in the Newtonian geometry. The radial profile of the disk effective temperature is also univoquely determined. The high energy spectrum can be calculated for a given lepton distribution. This offers an alternative picture to the standard accretion disk emission law. We discuss the application of this model to Active Galactic Nuclei, either for reproducing individual spectra, or for predicting new scaling laws that fit better the observed statistical properties.