X-ray polarization properties of the accretion column in magnetic CVs

The accretion column in magnetic Cataclysmic Variables may have a non negligible Thomson optical depth. A frac- tion of the thermal radiation from the post-shock region may therefore be scattered - and then polarized - before escaping the column. Moreover, part of the thermal radiation is reflected - and again polarized - by the White Dwarf surface. We show that X-ray polarimetry can provide valuable and probably unique information on the geometry and physical parameters of the ac- cretion column by calculating, by means of Monte Carlo simulations, the expected polarization properties of magnetic CVs as a function of the geometrical parameters (assuming a cylindrical geometry) and the Thomson optical depth of the column. We find that degrees of polarization as high as about 4% can be present, and apply our calculations to the archetypal magnetic CV, AM Herculis.