X-RAY-POLARIZATION IN THE 2-PHASE MODEL FOR AGN AND X-RAY BINARIES

We calculate the polarization properties of the two-phase model proposed by Haardt & Maraschi to explain the X-ray emission of AGN and X-ray binaries. In this model, hot electrons in an optically thin corona Comptonize the soft photons emitted by the underlying accretion disc to produce the X-rays. We find that the degree of polarization depends strongly on the inclination angle of the system, on the optical depth of the hot corona and on the assumed law for the soft flux. The main result is the strong dependence of the polarization properties on the energy, and in particular the orthogonality between the UV/soft X-ray and the hard X-ray polarizations.