Relativistic Reflection: Review and Recent Developments in Modeling

TL;DR

This paper reviews relativistic reflection in black hole systems, introduces the relxill model for improved self-consistent analysis, and discusses new methods to infer properties of the primary radiation source from reflection spectra.

Contribution

It presents the first combined approach in relativistic reflection modeling with the relxill model and introduces a new definition of reflection fraction in lamp post geometry.

Findings

Relxill model offers a more self-consistent reflection analysis.

New reflection fraction definition helps determine the primary source location.

Reflection spectra can constrain the high energy cutoff of the primary source.

Abstract

Measuring relativistic reflection is an important tool to study the innermost regions of the an accreting black hole system. In the following we present a brief review on the different aspects contributing to the relativistic reflection. The combined approach is for the first time incorporated in the new relxill model. The advantages of this more self-consistent approach are briefly summarized. A special focus is put on the new definition of the intrinsic reflection fraction in the lamp post geometry, which allows to draw conclusions about the primary source of radiation in these system. Additionally the influence of the high energy cutoff of the primary source on the reflection spectrum is motivated, revealing the remarkable capabilities of constraining $E_\mathrm{cut}$ by measuring relativistic reflection spectra from NuSTAR, preferably with lower energy coverage.