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The central region of M 31 observed with XMM-Newton. I. Group properties and diffuse emission

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journal contribution
posted on 24.10.2012, 09:21 by R. Shirey, R. Soria, K. Mason, K. Borozdin, W. Priedhorsky, J. P. Osborne, C. Hayter, M. G. Watson, R. G. West, A. Tiengo, M. Guainazzi, La Palombara N, S. Molendi, F. Paerels, W. Pietsch, A. M. Read
We present the results of a study based on an XMM-Newton Performance Verification observation of the central 30´of the nearby spiral galaxy M 31. In the 34-ks European Photon Imaging Camera (EPIC) exposure, we detect 116 sources down to a limiting luminosity of #1 10#2 erg s-1 (0.3-12 keV, d=760 kpc). The luminosity distribution of the sources detected with XMM-Newton flattens at luminosities below $\sim$ 2.5 1037 erg s-1 . We make use of hardness ratios for the detected sources in order to distinguish between classes of objects such as super-soft sources and intrinsically hard or highly absorbed sources. We demonstrate that the spectrum of the unresolved emission in the bulge of M 31 contains a soft excess which can be fitted with a $\sim$0.35-keV optically-thin thermal-plasma component clearly distinct from the composite point-source spectrum. We suggest that this may represent diffuse gas in the centre of M 31, and we illustrate its extent in a wavelet-deconvolved image.

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Citation

Astronomy & Astrophysics, 2001, 365 (1)

Version

VoR (Version of Record)

Published in

Astronomy & Astrophysics

Publisher

EDP Sciences for European Southern Observatory (ESO)

issn

0004-6361

Copyright date

2001

Available date

24/10/2012

Publisher version

http://www.aanda.org/articles/aa/abs/2001/01/aaxmm53/aaxmm53.html

Language

en

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