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

Chia-Ying Chiang, A. C. Fabian

Published 2011-04-22Version 1

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.