Inferring the coronal flaring patterns in active galactic nuclei from reverberation maps

Authors: R. Goyder; A. N. Lasenby

Source: Monthly Notices of the Royal Astronomical Society, Volume 353, Number 1, September 2004 , pp. 338-352(15)

Publisher: Wiley-Blackwell

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Abstract:

The relativistically broadened iron K alpha

line at 6.4 keV observed in the Seyfert 1 galaxy MCG–6-30-15 has provided a probe of the strong-gravity environment near a black hole, in particular suggesting that it is rapidly spinning. An important variable in such analyses is the geometry of the illuminating source. We present a new technique that constrains this geometry based on the spectral line shape, based on a model of discrete, point-like flaring regions in the X-ray corona. We apply it to simulated reverberation maps and give examples of successful reconstructions of complex coronal flaring patterns. For time-averaged spectral lines the problem is highly degenerate and so its inversion is more challenging. We quantify this degeneracy and give a measure of the spatial accuracy of the method in this case, before checking that it is consistent with the existing picture of MCG–6-30-15 by applying it to recent data from XMM–Newton.

Keywords: accretion, accretion discs; black hole physics; line: profiles; X-rays: general

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1365-2966.2004.08071.x

Publication date: 2004-09-01