Observations of MCG-5-23-16 with Suzaku, XMM-Newton and NuSTAR: Disk tomography and Compton hump reverberation

TL;DR

This study uses long multi-instrument X-ray observations of AGN MCG-5-23-16 to map emission regions via reverberation, revealing energy-dependent lags and the first detection of Compton hump reverberation in an AGN.

Contribution

It presents the first detection of Compton hump reverberation in an AGN and demonstrates the use of multi-time-scale reverberation mapping to spatially resolve emission regions.

Findings

Relativistic iron line detected in lag spectra across multiple time-scales.

First-time observation of a lag between energies above 10 keV and the primary continuum.

Reverberation of the Compton reflection hump responds to primary source changes.

Abstract

MCG-5-23-16 is one of the first AGN where relativistic reverberation in the iron K line originating in the vicinity of the supermassive black hole was found, based on a short XMM-Newton observation. In this work, we present the results from long X-ray observations using Suzaku, XMM-Newton and NuSTAR designed to map the emission region using X-ray reverberation. A relativistic iron line is detected in the lag spectra on three different time-scales, allowing the emission from different regions around the black hole to be separated. Using NuSTAR coverage of energies above 10 keV reveals a lag between these energies and the primary continuum, which is detected for the first time in an AGN. This lag is a result of the Compton reflection hump responding to changes in the primary source in a manner similar to the response of the relativistic iron K line.