2003/11/28 by Sebastien C. Vauclair, Alain Blanchard, Vauclair, Sebastien C. +3
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0311626
3 pages, proceeding of the Mykonos conference 'Multiwavelength Cosmology'
arxiv created 2003/11/28 · arxiv updated 2009/12/01
The evolution of the temperature distribution function (TDF) of X-ray clusters is kn own to be a powerful cosmological test of the density parameter of the Universe. Recent XMM observations allows us to measure accurately the L - T relation of high redshift X-ray clusters. In order to investigate cosmological implication of this recent results, we have derived theoretical number counts for different X-ray clusters samp les, namely the RDCS, EMSS, SHARC, 160 deg2 and MACS at z > 0.3 in different fl at models. We show that a standard hierarchical modeling of cluster distribution in a flat low density universe, normalized to the local abundance, overproduces cluster abundance at high redshift (z>0.5) by an order of magnitude. We conclude that presently existing data on X-ray clusters at high redshift strongly favor a universe with a high density of matter, insensitively to the details of the modeli ng.