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arXiv · 1903.04071

Constraining the Johannsen deformation parameter $\epsilon_3$ with black hole X-ray data

Ashutosh Tripathi·Askar B. Abdikamalov·Dimitry Ayzenberg·Cosimo Bambi·Sourabh Nampalliwar
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Abstract

We extend our previous work on tests of the Kerr black hole hypothesis using X-ray reflection spectroscopy and we infer observational constraints on the Johannsen deformation parameter $\epsilon_3$. We analyze a NuSTAR observation of the stellar-mass black hole in GS 1354-645, Suzaku data of the supermassive black holes in Ark 564, 1H0419-577, and PKS 0558-504, and some simultaneous XMM-Newton and NuSTAR observations of the supermassive black hole in MCG-6-30-15. All our measurements of $\epsilon_3$ are consistent with the Kerr metric and we find quite strong constraints from Ark 564 and MCG-6-30-15. We discuss the implications of our results and the next steps to improve our tests.

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Ashutosh Tripathi, Askar B. Abdikamalov, Dimitry Ayzenberg, Cosimo Bambi, Sourabh Nampalliwar. 2019-03-10. Constraining the Johannsen deformation parameter $\epsilon_3$ with black hole X-ray data. https://doi.org/10.1103/physrevd.99.083001

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