159 articles – 2000 Notices  [english version]
HAL : in2p3-00709900, version 1

Fiche détaillée  Récupérer au format
Astronomy and Astrophysics 525 (2011) A139
The galaxy cluster YSZ - LX and YSZ - M relations from the WMAP 5-yr data
J.-B. Melin1, J.G. Bartlett2, J. Delabrouille2, M. Arnaud3, R. Piffaretti3, G.W. Pratt3

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 REXCESS sample 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 Y^*500 = [ 1.60 ± 0.19] ×10-3 arcmin2 at M500 = 3 × 1014 h-1 M_&sun;, 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.
1 :  SPP - Service de Physique des Particules
2 :  APC - UMR 7164 - AstroParticule et Cosmologie
3 :  SAp - Service d'Astrophysique
APC - Cosmologie et Gravitation
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique
cosmology: observations – galaxies: clusters: general – galaxies: clusters: intracluster medium – cosmic background radiation – X-rays: galaxies: clusters