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 similar to 8 sigma level, yielding a combined constraint of f(gas)h = 0.08 +/- 0.01(ran) +/- 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 sigma 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 sigma level, which puts the average microwave luminosity ( at similar to 41 GHz) of bright cluster members (M-K 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.