Constraints on the missing baryons from the kinetic Sunyaev-Zeldovich effect in Planck data

Abstract

We estimate the amount of the {\it missing baryons} detected by the \Planck\ measurements of the cosmic microwave background in the direction of Central Galaxies (CGs) identified in the Sloan galaxy survey. The peculiar motion of the gas inside and around the CGs unveils values of the Thomson optical depth $τ_{\rm T}$ in the range $0.2$--$2\times 10^{-4}$, indicating that the regions probed around CGs contain roughly half of the total amount of baryons in the Universe at the epoch where the CGs are found. If baryons follow dark matter, the measured $τ_{\rm T}$s are compatible with the detection all the baryons existing inside and around the CGs.

Discussion on upper limits on kSZ dipole dropped to fit PRL length requirements. This version matches accepted version in Physical Review Letters