Constraining the KRZ deformation parameters I: limits from supermassive black hole X-ray data

Understand

X-ray reflection spectroscopy is a powerful technique for probing the nature of gravity around black holes in the so-called strong field regime.

• One of the most popular of such probes is to look at theory-agnostic deviations away from the Kerr solution, which is the only astrophysically relevant black hole solution within classical general relativity, in order to verify whether astrophysical black holes are described by the Kerr metric.
• We have recently extended our X-ray reflection spectroscopy framework to a class of very general axisymmetric non-Kerr black holes proposed by Konoplya, Rezzolla & Zhidenko (Phys.
• Rev.