Modelling the Broad-band Spectra of MCG-6-30-15 with a Relativistic Reflection Model

TL;DR

This paper demonstrates that a relativistic reflection model, combined with warm absorbers, can consistently explain the broad-band X-ray spectra and variability of the Seyfert galaxy MCG-6-30-15 across multiple observations.

Contribution

It presents a comprehensive spectral model that integrates warm absorbers with relativistic reflection, challenging absorption-dominated interpretations.

Findings

The reflection model fits data from 2001, 2004, and 2006 well.

Relativistic reflection explains both soft and hard X-ray excesses.

Warm absorbers are confirmed as significant spectral components.

Abstract

The spectrum of the bright Seyfert I galaxy MCG-6-30-15 shows a broad Fe K-alpha emission line, generally interpreted to originate very close to the central black hole which must then have a high spin. The observed X-ray variability is driven by a powerlaw component, with little variability found in the iron line energy band. The disconnection of continuum and line variability may be a consequence of strong gravitational light bending. The X-ray spectrum of MCG-6-30-15 is however complex, strongly modified at soft X-ray energies by warm absorbers, which some workers have extended to build an absorption-dominated model of the whole source behaviour. The absorption model interprets the whole X-ray spectrum without a relativistic reflection component and attributes most variability to the warm absorbers. We re-examine the XMM-Newton, Chandra and Suzaku data taken in 2001, 2004 and 2006, respectively, and construct a model consisting of several warm absorbers confirmed by spectral analysis, together with a relativistically blurred reflection component that explains both the soft and hard excesses as well. The model works well on data from all epochs, demonstrating that the reflection model provides a consistent interpretation of the broadband spectrum of MCG-6-30-15.