SIMBAD references

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 ∼8 σ level, yielding a combined constraint of f_gash=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 σ level, while both show an increasing trend with X-ray temperature. Nevertheless, our SZ estimated gas fraction is 30%-40% smaller than the concordance ΛCDM 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 σ level, which puts the average microwave luminosity (at ∼41 GHz) of bright cluster members (M_K≤-21) at (2.4±0.8)x10²⁷ h^–2 ergs/s/Hz. Furthermore, we can constrain the average dark matter halo concentration parameter to c_vir=3.4^+0.6_–0.9 for clusters with T_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.