Measuring Bulk Flows with the Kinematic Sunyaev-Zeldovich Effect in CMB Maps

Abstract.

We propose a new method to measure the possible large-scale bulk flows in the Universe from cosmic microwave background temperature anisotropy maps. At each cluster position, temperature fluctuations are a combination of Sunyaev-Zeldovich kinematic and thermal components, cosmological fluctuations and instrument noise. When averaged over many clusters the last three will integrate down, whereas the first one will be dominated by a possible bulk flow component. We get that at the 95% confidence level the bulk flows on scales $\ge 100h^{-1}$Mpc can be probed down to the amplitude of < 200 km/sec with the MAP data and down to only $\backsimeq 30$ km/sec with the Planck mission.