An XMM-Newton survey of broad iron lines in AGN

摘要

We report on the iron K alpha line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at iron-K is extremely common in the XMM-Newton spectra. Once appropriate soft X-ray absorption, narrow 6.4 keV emission and associated Compton reflection are accounted for, similar to 75% of the sample show an improvement when a further component is introduced. The typical properties of the broad emission are both qualitatively and quantitatively consistent with previous results from ASCA. The complexity is in general very well described by relativistic accretion disk models. In most cases the characteristic emission radius is constrained to be within similar to 50 R-g, where strong gravitational effects become important. We find in about 1/3 of the sample the accretion disk interpretation is strongly favoured over competing models. In a few objects no broad line is apparent. We find evidence for emission within 6R(g) in only two cases, both of which exhibit highly complex absorption. Evidence for black hole spin based on the X-ray spectra therefore remains tentative. (c) 2006 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim.