Wilkinson Microwave Anisotropy Probe Constraints on the Intracluster Medium

We devise a Monte Carlo-based, optimized filter match method to extract the thermal Sunyaev-Zel'dovich (SZ) signature of a catalog of 116 low-redshift X-ray clusters from the first-year data release of the Wilkinson Microwave Anisotropy Probe (WMAP). We detect an overall amplitude for the SZ signal at the 68 s level, yielding a combined constraint of f sub(gas)h = 0.08 c 0.01 (ran) c 0.01 (sys) on the gas mass fraction of the intracluster medium. We also compile X-ray-estimated gas fractions from the literature for our sample and find that they are consistent with the SZ estimates at the 2 s level, while both show an increasing trend with X-ray temperature. Nevertheless, our SZ estimated gas fraction is 30%-40% smaller than the concordance [Lambda] CDM cosmic average. We also express our observations in terms of the SZ flux-temperature relation and compare it with other observations, as well as with numerical studies. Based on its spectral and spatial signature, we can also extract the microwave point-source signal of the clusters at the 3 s level, which puts the average microwave luminosity (at 641 GHz) of bright cluster members (M sub(K) , -21) at (2.4 c 0.8) x 10 super(27) h super(-2) ergs s super(-1) Hz super(-1). Furthermore, we can constrain the average dark matter halo concentration parameter to c sub(vir) = 3.4 super(+) sub(-) super(0) sub(0) super(.) sub(.) super(6) sub(9) for clusters with T sub(X) > 5 keV. Our work serves as an example for how correlation of SZ surveys with cluster surveys at other frequencies can significantly increase our physical understanding of the intracluster medium.