On the Presence of Thermal SZ Induced Signal in WMAP Temperature Maps

Using available optical and X-ray catalogues of clusters and superclusters of galaxies, we build templates of tSZ emission as they should be detected by the WMAP experiment. We compute the cross-correlation of our templates with WMAP temperature maps, and interpret our results separately for clusters and for superclusters of galaxies. For clusters of galaxies, we claim 2-5 $\sigma$ detections in our templates built from BCS (Ebeling 1998, 2000), NORAS (Boehringer 2000) and PSPC (Vikhlinin 1998) catalogues. In these templates, the typical cluster temperature decrements in WMAP scans are around 15-35 $\mu$K in the RJ range (no beam deconvolution applied). Our results are robust with respect to foreground contamination. In supercluster scales, we detect a diffuse component in the V & W WMAP bands which cannot be generated by superclusters in our catalogues, and which is not present in the clean map of Tegmark, de Oliveira-Costa & Hamilton (2003). Analyses in this clean map yield the following upper limit for the comptonization parameter associated to supercluster scales: $y_{SC} < 3.12 \times 10^{-8}$ at the 95% confidence limit.