Toward Precision Tests of General Relativity with Black Hole X-Ray Reflection Spectroscopy

Abstract

Abstract Astrophysical black hole systems are the ideal laboratories for testing Einstein’s theory of gravity in the strong field regime. We have recently developed a framework that uses the reflection spectrum of black hole systems to perform precision tests of general relativity by testing the Kerr black hole hypothesis. In this paper, we analyze XMM-Newton and NuSTAR observations of the supermassive black hole in the Seyfert 1 galaxy MCG–06–30–15 with our disk reflection model. We consider the Johannsen metric with the deformation parameters α 13 and α 22, which quantify deviations from the Kerr metric. For α 22 = 0, we obtain the black hole spin and . For α 13 = 0, we obtain and . The Kerr solution is recovered for α 13 = α 22 = 0. Thus, our results include the Kerr solution within statistical uncertainties. Systematic uncertainties are difficult to account for, and we discuss some issues in this regard.