S-Z Power Spectra
  There is some observational evidence for earlier evolution of clusters of galaxies than predicted in the standard LambdaCDM model with a Gaussian primordial density fluctuation field, and a low value for the mass variance parameter sigma_8. Particularly difficult in this model is the interpretation of possible excess CMB anisotropy on cluster scales as due to the Sunyaev-Zeldovich (S-Z) effect. We have calculated S-Z power spectra in the standard model, and in two alternative models which predict higher cluster abundance - a model with non-Gaussian PDF, and an early dark energy model. As anticipated, the levels of S-Z power in the latter two models are significantly higher than in the standard model, and in good agreement with current measurements of CMB anisotropy at high multipole values. Our results provide a sufficient basis for testing the viability of the three models by futur high quality measurements of cluster abundance and the anisotropy induced by the S-Z effect. 
Yoel Rephaeli and Sharon Sadeh