The structural and scaling properties of nearby galaxy clusters

Free access article

Issue		A&A Volume 441, Number 3, October III 2005


Page(s)		893 - 903
Section		Cosmology (including clusters of galaxies)
DOI		http://dx.doi.org/10.1051/0004-6361:20052856

A&A 441, 893-903 (2005)
DOI: 10.1051/0004-6361:20052856

II. The M-T relation

M. Arnaud¹, E. Pointecouteau¹ and G. W. Pratt²

¹ CEA/DSM/DAPNIA Service d'Astrophysique, CE Saclay, L'Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette, France
e-mail: marnaud@discovery.saclay.cea.fr
² MPE, Giessenbachstraße, 85748 Garching, Germany

(Received 10 February 2005 / Accepted 19 June 2005 )

Abstract
Using a sample of ten nearby ( $z\lesssim 0.15$ ), relaxed galaxy clusters in the temperature range [2-9] $~\rm keV$ , we have investigated the scaling relation between the mass at various density contrasts ( $\delta=2500,1000,500,200$ ) and the cluster temperature. The masses are derived from NFW-type model fits to mass profiles, obtained under the hydrostatic assumption using precise measurements, with , at least down to $\delta=1000$ . The logarithmic slope of the M-T relation is well constrained and is the same at all $\delta$ , reflecting the self-similarity of the mass profiles. At $\delta=500$ , the slope of the relation for the sub-sample of hot clusters ( $kT>3.5~\rm keV$ ) is consistent with the standard self-similar expectation: $\alpha= 1.49\pm0.15$ . The relation steepens when the whole sample is considered: $\alpha=1.71\pm0.09$ . The normalisation of the relation is discrepant (by ~30 per cent), at all density contrasts, with the prediction from purely gravitation based models. Models that take into account radiative cooling and galaxy feedback are generally in better agreement with our data. We argue that remaining discrepancies, in particular at low $\delta$ , are more likely due to problems with models of the ICM thermal structure rather than to an incorrect estimate of the mass from X-ray data.

Key words: cosmology: observations -- cosmology: dark matter -- galaxies: clusters: general -- galaxies: intergalactic medium -- X-rays: galaxies: clusters

SIMBAD Objects

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.