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XMM–Newton observations of high-luminosity radio-quiet quasi-stellar objects

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journal contribution
posted on 24.10.2012, 09:22 by Kim L. Page, J. N. Reeves, Paul T. O'Brien, Martin J. L. Turner, D. M. Worrall
XMM–Newton observations of five high-luminosity radio-quiet quasi-stellar objects (QSOs; Q 0144−3938, UM 269, PG 1634+706, SBS 0909+532 and PG 1247+267) are presented. Spectral energy distributions were calculated from the XMM–Newton European Photon Imaging Camera (EPIC) and Optical Monitor (OM) data, with bolometric luminosities estimated in the range from 7 × 10[superscript 45] to 2 × 10[superscript 48] erg s[superscript −1] for the sample, peaking in the ultraviolet. At least four of the QSOs show a similar soft excess, which can be well modelled by either one or two blackbody components, in addition to the hard X-ray power law. The temperatures of these blackbodies (∼100–500 eV) are too high to be direct thermal emission from the accretion disc, so Comptonization is suggested. Two populations of Comptonizing electrons, with different temperatures, are needed to model the broad-band spectrum. The hotter of these produces what is seen as the hard X-ray power law, while the cooler (∼0.25–0.5 keV) population models the spectral curvature at low energies. Only one of the QSOs shows evidence for an absorption component, while three of the five show neutral iron emission. Of these, PG 1247+267 seems to have a broad line (with an equivalent width of ∼250 eV), with a strong, associated reflection component (R ∼ 2), measured out to 30 keV in the rest frame of the QSO. Finally, it is concluded that the X-ray continuum shape of active galactic nuclei remains essentially constant over a wide range of black hole mass and luminosity.

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Citation

Monthly Notices of the Royal Astronomical Society, 2004, 353 (1), pp. 133-142

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press (OUP) on behalf of the Royal Astronomical Society

issn

0035-8711

eissn

1365-2966

Copyright date

2004

Available date

24/10/2012

Publisher version

http://mnras.oxfordjournals.org/content/353/1/133

Language

en

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