POLARIZATION PROPERTIES OF EMISSION-LINES FROM RELATIVISTIC ACCRETION DISKS

We investigate the polarization properties of line emission originating in a geometrically thin, relativistic, Keplerian disk. The detailed derivation of formulae for calculating the line profile as well as its polarization is presented. We find that general relativistic effects on the line profile, especially on the polarization of the line, can be strong. Therefore, polarimetric observation will provide an invaluable diagnostic for the origin of the lines. The very broad X-ray K-alpha lines observed from many accretion powered sources are good candidates for the application of our results. These lines provide an important clue to processes in the innermost region of the accretion disk, where many uncertainties remain.