Please use this identifier to cite or link to this item:
Title: A simultaneous XMM-Newton and BeppoSAX observation of the archetypal broad line Seyfert 1 galaxy NGC 5548
Authors: Pounds, Kenneth Alwyne
Reeves, J. N.
Page, K. L.
Edelson, R.
Matt, G.
Perola, G. C.
First Published: 21-May-2003
Publisher: Royal Astronomical Society
Citation: Monthly Notices of the Royal Astronomical Society, 2003, 341 (3), pp. 953-960
Abstract: We report the spectral analysis of a long XMM–Newton observation of the well-studied, moderate luminosity broad line Seyfert 1 galaxy NGC 5548. The source was at an historically average brightness and we find the hard (3–10 keV) spectrum can be well fitted by a power law of photon index Γ∼ 1.75, together with reflection. The only feature in the hard X-ray spectrum is a narrow emission line near 6.4 keV, with an equivalent width of ∼60 eV. The energy and strength of this line are consistent with fluorescence from ‘neutral’ iron distant from the central continuum source. We find no evidence for a broad Fe K line, with an upper limit well below previous reports, suggesting the inner accretion disc is now absent or highly ionized. The addition of simultaneous BeppoSAX data allows the analysis to be extended to 200 keV, yielding important constraints on the total reflection. Extrapolation of the hard X-ray power law down to 0.3 keV shows a clear ‘soft excess’ below ∼0.7 keV. After due allowance for the effects of a complex warm absorber, measured with the XMM–Newton RGS, we find that the soft excess is better described as a smooth upward curvature in the continuum flux below ∼2 keV. The soft excess can be modelled either by Comptonized thermal emission or by enhanced reflection from the surface of a highly ionized disc.
DOI Link: 10.1046/j.1365-8711.2003.06470.x
ISSN: 0035-8711
eISSN: 1365-2966
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2003 RAS. All rights reserved. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

Files in This Item:
File Description SizeFormat 
MNRAS-2003-Pounds-953-60.pdfPublished (publisher PDF)348.33 kBAdobe PDFView/Open

Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.