2018/11/30 by Ashutosh Tripathi, Sourabh Nampalliwar, Askar B. Abdikamalov +5 · 2 citations
Physics and Astronomy · #gr-qc #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/ab0e7e
published as Astrophys.J. 875: 56 (2019) · 10 pages, 7 figures. v2: title slightly changed, arXiv version shorter than published version
arxiv created 2019/04/17 · arxiv updated 2019/04/18
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 which 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 α13 and α22, which quantify deviations from the Kerr metric. For α22 = 0, we obtain the black hole spin 0.928 < a_* < 0.983 and -0.44 < α13 < 0.15. For α13 = 0, we obtain 0.885 < a_* < 0.987 and -0.12 < α22 < 1.05. The Kerr solution is recovered for α13 = α22 = 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.