Volume 525, January 2011
|Number of page(s)||11|
|Section||Cosmology (including clusters of galaxies)|
|Published online||09 December 2010|
The galaxy cluster YSZ−LX and YSZ−M relations from the WMAP 5-yr data
DSM/Irfu/SPP, CEA/Saclay, 91191
2 APC – Université Paris Diderot, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
3 APC – CNRS, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
4 DSM/Irfu/SAp, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France
e-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Accepted: 21 October 2010
We use multifrequency matched filters to estimate, in the WMAP 5-year data, the Sunyaev-Zel’dovich (SZ) fluxes of 893 ROSAT NORAS/REFLEX clusters spanning the luminosity range LX,[0.1−2.4] keV = 2 × 1041−3.5 × 1045 erg s-1. The filters are spatially optimised by using the universal pressure profile recently obtained from combining XMM-Newton observations of the REXCESSsample and numerical simulations. Although the clusters are individually only marginally detected, we are able to firmly measure the SZ signal (>10σ) when averaging the data in luminosity/mass bins. The comparison between the bin-averaged SZ signal versus luminosity and X-ray model predictions shows excellent agreement, implying that there is no deficit in SZ signal strength relative to expectations from the X-ray properties of clusters. Using the individual cluster SZ flux measurements, we directly constrain the Y500−LX and Y500−M500 relations, where Y500 is the Compton y-parameter integrated over a sphere of radius r500. The Y500−M500 relation, derived for the first time in such a wide mass range, has a normalisation at M500 = 3 × 1014 h-1 M⊙, in excellent agreement with the X-ray prediction of 1.54 × 10-3 arcmin2, and a mass exponent of α = 1.79 ± 0.17, consistent with the self-similar expectation of 5/3. Constraints on the redshift exponent are weak due to the limited redshift range of the sample, although they are compatible with self-similar evolution.
Key words: cosmology: observations / galaxies: clusters: general / galaxies: clusters: intracluster medium / cosmic background radiation / X-rays: galaxies: clusters
© ESO, 2010
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