Polarization of Comptonized photons

The polarization of Comptonized X-rays as a function of energy and emission angle is obtained. The geometry utilized is that of the semi-infinite plane with the source photons located on a plane at a finite optical depth below the surface. It is further shown what information is obtainable from polarization measurements at only two different energies. The observed values for the X-ray sources Cyg X-1 and Sco X-1 are used to illustrate the calculations.