Probing relativistic effects in the central engine of AGN

TL;DR

This paper introduces a new relativistic X-ray spectral model for AGN eclipses, demonstrating how relativistic effects influence observable features and applying it to real data to improve understanding of the central engine.

Contribution

The paper presents a novel relativistic model for X-ray eclipses in AGN, incorporating detailed observables and applying it to actual XMM-Newton data for the first time.

Findings

Absorption varies with photon energy, peaking when the approaching side of the X-ray source is covered.

Relativistic effects significantly influence eclipse observables in AGN.

Model fitting to real data shows improved understanding of the black hole environment.

Abstract

Active Galactic Nuclei (AGN) are perfect laboratories to check General Relativity (GR) effects by using Broad Line Region (BLR) clouds eclipses to probe the innermost regions of the accretion disk. A new relativistic X-ray spectral model for X-ray eclipses is introduced. First we present the different observables that are involved in X-ray eclipses, including the X-ray emitting regions size, the emissivity index, the cloud's column density, ionization, size and velocity, the black hole spin, and the system's inclination. Then we highlight some theoretical predictions on the observables by using XMM-Newton simulations, finding that absorption varies depending on the photons' energy range, being maximum when the approaching side of the X-ray-emitting region is covered. Finally, we fit our relativistic model to actual XMM-Newton data from a long observation of the NLS1 galaxy SWIFT J2127.4+5654, and compare our results with a previous work, in which we addressed the BLR cloud eclipse from a non-relativistic prespective.