WMAP Observations of Planck ESZ Clusters

Abstract

We examine the Sunyaev--Zeldovich (SZ) effect in the 7-yr Wilkinson Microwave Anisotropy Probe (WMAP) data by cross-correlating it with the Planck Early-release Sunyaev--Zeldovich catalog. Our analysis proceeds in two parts. We first perform a stacking analysis in which the filtered WMAP data are averaged at the locations of the 175 Planck clusters. We then perform a regression analysis to compare the mean amplitude of the SZ signal, Y_{500}, in the WMAP data to the corresponding amplitude in the Planck data. The aggregate Planck clusters are detected in the 7-yr WMAP data with a signal-to-noise ratio of 16.3. In the regression analysis we find that the SZ amplitude measurements agree to better than 25%: $a=1.23 \pm 0.18$ for the fit Y^{wmap}_{500} = aY^{planck}_{500}$.