Large scale pressure fluctuations and the Sunyaev-Zel'dovich effect - art.no. 103506

The Sunyaev-Zel'dovich (SZ) effect associated with pressure fluctuations of the large scale structure gas distribution will be probed with current and upcoming wide-field small angular scale cosmic microwave background experi ments. We study the generation of pressure fluctuations by baryons which ar e present in virialized dark matter halos, with overdensities greater than or similar to 200 and by baryons present in overdensities less than or simi lar to 10. For collapsed halos, assuming the gas distribution is in hydrost atic equilibrium with matter density distribution, we predict the pressure power spectrum and bispectrum associated with the large scale structure gas distribution by extending the dark matter halo approach which describes th e density field in terms of correlations between and within halos. The proj ected pressure power spectrum allows a determination of the resulting SZ po wer spectrum due to virialized structures. The unshocked photoionized baryo ns present in smaller overdensities trace the Jeans-scale smoothed dark mat ter distribution. They provide a lower limit to the SZ effect due to large scale structure in the absence of massive collapsed halos. We extend our ca lculations to discuss higher order statistics, such as bispectrum and skewn ess in SZ data. The SZ-weak lensing cross correlation is suggested as a pro be of correlations between dark matter and baryon density fields, while the probability distribution functions of peak statistics of SZ halos in wide field CMB data can be used as a probe of cosmology and non-Gaussian evoluti on of large scale pressure fluctuations.