Evidence of the Missing Baryons from the Kinematic Sunyaev-Zeldovich Effect in Planck Data.

We estimate the amount of the 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(T) in the range 0.2-2×10(-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.

On the Number Density of Sunyaev-Zeldovich Clusters of Galaxies.

If the mean properties of clusters of galaxies are well described by the entropy-driven model, the distortion induced by the cluster population on the blackbody spectrum of the cosmic microwave background radiation is proportional to the total amount of intracluster gas, while temperature anisotropies are dominated by the contribution of 1014 M middle dot in circle clusters. This result depends marginally on cluster parameters, and it can be used to estimate the number density of clusters with enough hot gas to produce a detectable Sunyaev-Zeldovich effect. Comparing different cosmological models, the relation depends mainly on the density parameter Omegam.