Non-Gaussian aspects of thermal and kinetic Sunyaev-Zel'dovich effects - art. no. 063514

We discuss non-Gaussian effects associated with the local large-scale struc ture contributions to the cosmic microwave background (CMB) anisotropies th rough the thermal Sunvaev-Zel'dovich (SZ) effect. The non-Gaussianities ass ociated with the SZ effect arise from the existence of a significant four-p oint correlation function in large scale pressure fluctuations. Using the p ressure trispectrum calculated under the recently popular halo model. we di scuss the full covariance of the SZ thermal power spectrum. We use this ful l covariance matrix to study the astrophysical uses of the SZ effect and di scuss the extent to which gas proper-ties can be derived from a measurement of the SZ power spectrum. With the SZ thermal effect separated in temperat ure fluctuations using its frequency information, the kinetic SZ effect. al so known as the Ostriker-Vishniac effect, is expected to dominate the CMB t emperature fluctuations at small angular scales. This effect arises from th e baryon modulation of the first order Doppler effect resulting from the re lative motion of scatterers. The presence of the SZ kinetic effect can be d etermined through a cross-correlation between the SZ thermal and a CMB map at small scales. Since the SZ kinetic effect is second order, however. cont ributions to such a cross-correlation arise to lower order in the form of a three-point correlation function, or a bispectrum in Fourier space. We sug gest an additional statistic that can be used to study the correlation betw een pressure traced by the SZ thermal effect and the baryons traced by the SZ kinetic effect involving the cross-power spectrum constructed through sq uared temperatures instead of the usual temperature itself. Through a signa l-to-noise calculation, we show that future small angular scale multifreque ncy CMB experiments, sensitive to multipoles of a few thousand, will be abl e to measure the cross-correlation of SZ thermal and SZ kinetic effects thr ough a temperature squared power spectrum.