A reflection model with a radial disk density profile

Abstract

In this paper we present RELXILLDGRAD_NK, a relativistic reflection model in which the electron density of the accretion disk is allowed to have a radial power-law profile. The ionization parameter has also a non-constant radial profile and is calculated self-consistently from the electron density and the emissivity. We show the impact of the implementation of the electron density gradient in our model by analyzing a NuSTAR spectrum of the Galactic black hole in EXO 1846-031 during its last outburst in 2019 and a putative future observation of the same source with Athena and eXTP. For the NuSTAR spectrum, we find that the new model provides a better fit, but there is no significant difference in the estimation of the model parameters. For the Athena+eXTP simulation, we find that a model without a disk density profile is unsuitable to test the spacetime metric around the compact object, in the sense that modeling uncertainties can incorrectly lead to finding a non-vanishing deformation from the Kerr solution.

11 pages, 9 figures. v2: refereed version

References in corpus (9)

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Cited by in corpus (5)

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• Black Hole Spin Measurements Based on a Thin Disc Model with Finite Thickness I. An example study of MCG-06-30-15
• Testing Gravity with Black Hole X-Ray Data
• Testing the $\delta$-Kerr metric with black hole X-ray data
• Impact of ionization and electron density gradients in X-ray reflection spectroscopy measurements