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Issue A&A
Volume 391, Number 3, September I 2002
Page(s) 841 - 855
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20020905



A&A 391, 841-855 (2002)
DOI: 10.1051/0004-6361:20020905

Gravitating mass profiles of nearby galaxy clusters and relations with X-ray gas temperature, luminosity and mass

S. Ettori1, S. De Grandi2 and S. Molendi3

1  European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
2  Osservatorio Astronomico di Brera, via Bianchi 46, 23807 Merate (LC), Italy
3  Istituto di Fisica Cosmica "G.Occhialini", via Bassini 15, 20133 Milano, Italy

(Received 24 February 2002 / Accepted 7 June 2002 )

Abstract
We consider a sample of 22 nearby clusters of galaxies observed with the Medium Energy Concentrator Spectrometer (MECS) on board BeppoSAX . They cover the range in gas temperature between 3 and 10 keV, with bolometric X-ray luminosity between $2 \times 10^{44}$ erg s -1 and $6 \times 10^{45}$ erg s -1. Using the de-projected gas temperature and density profiles resolved in a number of bins between 5 and 7 and obtained from this dataset only, we recover the total gravitating mass profiles for 20 objects just applying the (i) spherical symmetry and (ii) hydrostatic equilibrium assumptions. We investigate the correlations between total mass, gas temperature and luminosity at several overdensities values and find that the slopes of these relations are independent of the considered overdensity and consistent with what is predicted from the cluster scaling laws. The best-fit results on the normalization of the M-T relation are slightly lower, but still consistent considering the large errors that we measure, with hydrodynamical simulations. A segregation between relaxed and non-relaxed systems is present in each plane of these relations pointing out a significant component in their intrinsic scatter. This segregation becomes more evident at higher overdensities and when physical quantities, like $M_{\rm gas}$ and L, that are direct functions of the amount of gas observed, are considered.


Key words: galaxies: cluster: general -- galaxies: fundamental parameters -- intergalactic medium -- X-ray: galaxies -- cosmology: observations -- dark matter

Offprint request: S. Ettori, settori@eso.org

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© ESO 2002


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