Improved Reflection Models of Black-Hole Accretion Disks: Treating the Angular Distribution of X-rays

Abstract: X-ray reflection models are used to constrain the properties of the accretion disk, such as the degree of ionization of the gas and the elemental abundances. In combination with general relativistic ray tracing codes, additional parameters like the spin of the black hole and the inclination to the system can be determined. However, current reflection models used for such studies only provide angle-averaged solutions for the flux reflected at the surface of the disk. Moreover, the emission angle of the photons changes over the disk due to relativistic light bending. To overcome this simplification, we have constructed the new angle-dependent reflection model RELXILL, by self-consistently connecting the XILLVER reflection models with the relativistic blurring code RELLINE.