Compton Scattering of Polarized Radiation in Two‐Phase Accretion Disks in Active Galactic Nuclei

We present results of radiative transfer calculations of Compton scatteringof polarized radiation in a corona above an accretion disk. The corona has aplane-parallel geometry and is assumed to be homogeneous with a fixedtemperature. We employ a Feautrier method to calculate the radiative transfer,incorporating the full relativistic, polarized Compton redistribution matrix.This allows us to explore a broad range of parameter space, in particular largeoptical depths and/or low corona temperatures, for which the iterativescattering method is very inefficient. Compared to Thomson scattering, Comptonscattering generally produces smaller polarizations for featureless spectra.Distinct frequency-dependent patterns in polarization are produced near linesand edges, which can be used as diagnostics for the corona. We discuss thephysics which gives rise to these results. Compton scattering can smear outLyman edges in total flux, and at the same time produce large increases inpolarization. This might help explain the steep rises in polarization observednear the Lyman limit in some quasars.Comment: 22 pages, 18 figures, use AASTeX style file aaspp4.st