Is the soft excess in active galactic nuclei real?

Gierlinski, M.; Done, C.

doi:10.1111/j.1365-2966.2004.07687.x

Is the soft excess in active galactic nuclei real?

Gierlinski, M.; Done, C.

Authors

M. Gierlinski

Professor Christine Done chris.done@durham.ac.uk
Professor

Abstract

We systematically analyse all publicly available XMM–Newton spectra of radio-quiet PG quasars. The soft X-ray excess in these objects is well modelled by an additional, cool, Compton scattering region. However, the remarkably constant temperature derived for this component over the whole sample requires a puzzling fine tuning of the parameters. Instead, we propose that the soft excess is an artifact of strong, relativistically smeared, partially ionized absorption. The strong jump in opacity at 0.7 keV from O vii, O viii and iron can lead to an apparent soft excess below this energy, which is trivially constant since it depends on atomic processes. This can have a dramatic effect on the derived spectrum, which has implications for fitting the relativistic smearing of the reflected iron line emission from the disc.

Citation

Gierlinski, M., & Done, C. (2004). Is the soft excess in active galactic nuclei real?. Monthly Notices of the Royal Astronomical Society, 349(1), L7-L11. https://doi.org/10.1111/j.1365-2966.2004.07687.x

Journal Article Type	Article
Publication Date	2004-03
Deposit Date	Feb 27, 2008
Publicly Available Date	Aug 11, 2014
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	349
Issue	1
Pages	L7-L11
DOI	https://doi.org/10.1111/j.1365-2966.2004.07687.x
Keywords	Accretion discs, Atomic processes, X-rays, Galaxies.

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This article has been accepted for publication in Monthly notices of the Royal Astronomical Society © 2004 The Authors Published on behalf of Royal Astronomical Society. All rights reserved.