Spectropolarimetric properties of radiation, Comptonized in a slab geometry representing the disk-corona system. (a) Energy dependence of the PD as observed at an inclination i = 35° for the outflow velocities v = 0 (solid) and v = 0.3c (dashed) and two values of the blackbody temperature of seed photons, kT_seed = 0.05 keV (black) and 0.25 keV (red), corresponding to the color temperatures in our fitted disk model at ≃100R_g and ≃10R_g, respectively. In all cases, the Comptonization parameters are kT_e = 25 keV and τ = 0.75, which correspond to the corona parameters found in Sect. 4. (b) Corresponding energy spectra. (c) Corresponding PA for v = 0; for v = 0.3c, PA = 0° at all energies.