The galaxy cluster Ysz-Lx and Ysz-M relations from the WMAP 5-yr data - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: 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 spanningthe luminosity range Lx,0.1-2.4keV = 2 10^{41} - 3.5 10^{45} erg s^{-1}. Thefilters are spatially optimised by using the universal pressure profilerecently obtained from combining XMM-Newton observations of the REXCESS sampleand numerical simulations. Although the clusters are individually onlymarginally detected, we are able to firmly measure the SZ signal >10 sigmawhen averaging the data in luminosity-mass bins. The comparison between thebin-averaged SZ signal versus luminosity and X-ray model predictions showsexcellent agreement, implying that there is no deficit in SZ signal strengthrelative to expectations from the X-ray properties of clusters. Using theindividual cluster SZ flux measurements, we directly constrain the Y500-Lx andY500-M500 relations, where Y500 is the Compton y-parameter integrated over asphere of radius r500. The Y500-M500 relation, derived for the first time insuch a wide mass range, has a normalisation Y*500=1.60 pm 0.19 10^{-3}arcmin^2 at M500=3 10^{14} h^{1} Msun, in excellent agreement with the X-rayprediction of 1.54 10^{-3} arcmin^2, and a mass exponent of alpha=1.79 pm 0.17,consistent with the self-similar expectation of 5-3. Constraints on theredshift exponent are weak due to the limited redshift range of the sample,although they are compatible with self-similar evolution.



Autor: J.-B. Melin, J. G. Bartlett, J. Delabrouille, M. Arnaud, R. Piffaretti, G. W. Pratt

Fuente: https://arxiv.org/







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