Public Release of RELXILL_NK: A Relativistic Reflection Model for Testing Einstein's Gravity
We present the public release version of relxill_nk, an X-ray reflection model for testing the Kerr hypothesis and general relativity. This model extends the relxill model that assumes the black hole (BH) spacetime is described by the Kerr metric. We also present relxilllp_nk, the first non-Kerr X-ray reflection model with a lamppost corona configuration, as well as all other models available in the full relxill_nk package. In all models the relevant relativistic effects are calculated through a general relativistic ray-tracing code that can be applied to any well-behaved, stationary, axisymmetric, and asymptotically flat BH spacetime. We show that the numerical error introduced by using a ray-tracing code is not significant compared with the observational error present in current X-ray reflection spectrum observations. In addition, we present the reflection spectrum for the Johannsen metric as calculated by relxill_nk.
© 2019 The American Astronomical Society. Received 2019 February 28; revised 2019 May 1; accepted 2019 May 5; published 2019 June 18. We thank Alejandro Cardenas-Avendano for earlier collaboration on the subject of this paper. This work was supported by the Innovation Program of the Shanghai Municipal Education Commission, grant No. 2019-01-07-00-07-E00035, the National Natural Science Foundation of China (NSFC), grant No. U1531117, and Fudan University, grant No. IDH1512060. A.B.A. also acknowledges the support from the Shanghai Government Scholarship (SGS). J.A.G. acknowledges support from the Alexander von Humboldt Foundation. S.N. acknowledges support from the Excellence Initiative at Eberhard-Karls Universität Tübingen.
Submitted - 1902.09665.pdf
Published - Abdikamalov_2019_ApJ_878_91.pdf