Constraints on the SZ Power Spectrum on Degree Angular Scales in WMAP Data

Understand

The Sunyaev-Zel'dovich (SZ) effect has a distinct spectral signature that allows its separation from fluctuations in the cosmic microwave background (CMB) and foregrounds.

• Using CMB anisotropies measured in Wilkinson Microwave Anisotropy Probe's five-year maps, we constrain the SZ fluctuations at large, degree angular scales corresponding to multipoles in the range from 10 to 400.
• We provide upper bounds on SZ fluctuations at multipoles greater than 50, and find evidence for a hemispherically asymmetric signal at ten degrees angular scales.
• The amplitude of the detected signal cannot be easily explained with the allowed number density and temperature of electrons in the Galactic halo.