Tentative Detection of Quasar Feedback from WMAP and SDSS Cross-Correlation

We perform a cross-correlation analysis of microwave data from Wilkinson Microwave Anisotropy Probe and photometric quasars from the Sloan Digital Sky Survey, testing for Sunyaev-Zeldovich (SZ) effect from quasars. A statistically significant (2.5 $\sigma$) temperature decrement exists in the 41 GHz microwave band. A two-component fit to the cross-correlation spectrum incorporating both dust emission and SZ yields a best-fit $y$ parameter of $(7.0 \pm 3.4)\times 10^{-7}$. A similar cross-correlation analysis with the Luminous Red Galaxy sample from Sloan gives a best-fit $y$ parameter of $(5.3 \pm 2.5)\times 10^{-7}$. We discuss the possible physical origin of these signals, which is likely a combination of SZ effects from quasars and from galaxy clusters. Both the Planck Surveyor satellite and current ground-based arcminute-resolution microwave experiments will detect this signal with a higher statistical significance.