218 articles – 619 references  [version française]
 HAL: hal-00004520, version 1
 arXiv: astro-ph/0503426
 Astronomy and Astrophysics 437 (2005) 31-38
 $XMM-Newton$ $\Omega$ project: III. Gas mass fraction shape in high redshift clusters
 (2005)
 We study the gas mass fraction, $f_{\rm gas},$ behavior in $XMM-Newton$ $\Omega$ project. The typical $f_{\rm gas}$ shape of high redshift galaxy clusters follows the global shape inferred at low redshift quite well. This result is consistent with the gravitational instability picture leading to self similar structures for both the dark and baryonic matter. However, the mean $f_{\rm gas} in distant clusters shows some differences to local ones, indicating a departure from strict scaling. This result is consistent with the observed evolution in the luminosity-temperature relation. We quantitatively investigate this departure from scaling laws. Within the local sample we used, a moderate but clear variation of the amplitude of the gas mass fraction with temperature is found, a trend that weakens in the outer regions. These variations do not explain departure from scaling laws of our distant clusters. An important implication of our results is that the gas fraction evolution, a test of the cosmological parameters, can lead to biased values when applied at radii smaller than the virial radius. From our$XMM\$ clusters, the apparent gas fraction at the virial radius is consistent with a non-evolving universal value in a high matter density model and not with a concordance.
 Subject : Physics/Astrophysics/Cosmology and Extra-Galactic AstrophysicsSciences of the Universe/Astrophysics
 Keyword(s) : Galaxies: clusters: general-galaxies:intergalactic medium – Cosmology:cosmological parameters – dark matter – X-rays: galaxies: clusters
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 hal-00004520, version 1 http://hal.archives-ouvertes.fr/hal-00004520 oai:hal.archives-ouvertes.fr:hal-00004520 From: Alain Blanchard <> Submitted on: Saturday, 19 March 2005 11:00:06 Updated on: Monday, 26 June 2006 15:14:47