Relativistic Reflection: The Impact of Returning Radiation on Black Hole Spin Measurements
Remeis Observatory & ECAP
Relativistic reflection of X-ray radiation at the inner accretion disk around black holes has been extensively studied in the last decade. The emitted spectrum, which likely originates from a compact corona close to the black hole, is strongly blurred due to gravity effects. Encoded in this blurring of the observed spectrum are important system parameters such as the black hole spin or location and geometry of the primary source of radiation. While several relativistic reflection models already exist, a crucial effect has so far been neglected: a larger fraction of reflected radiation from the inner regions will inevitably return to the accretion disk and produce additional reflection. The first implementation of reflection from returning radiation in the RELXILL model suite and a thorough analysis of the implications is presented in Dauser et al. (submitted).