On the number density of Sunyaev-Zeldovich clusters of galaxies

If the mean properties of clusters of galaxies are well described by the en tropy-driven model, the distortion induced by the cluster population on the blackbody spectrum of the cosmic microwave background radiation is proport ional to the total amount of intracluster gas, while temperature anisotropi es are dominated by the contribution of 10(14) M. clusters. This result dep ends marginally on cluster parameters, and it can be used to estimate the n umber density of clusters with enough hot gas to produce a detectable Sunya ev-Zeldovich effect. Comparing different cosmological models, the relation depends mainly on the density parameter Omega(m). If the number density of clusters could be estimated by a different method, then this dependence cou ld be used to constrain Omega(m).