Correlation Properties of the Kinematic Sunyaev-Zel'dovich Effect and Implications for Dark Energy

In the context of a cosmological study of bulk flows in the universe, we present a detailed study of the statistical properties of the kinematic Sunyaev-Zel'dovich (kSZ) effect. We first compute analytically the correlation function and the power spectrum of the projected peculiar velocities of galaxy clusters. By taking into account the spatial clustering properties of these sources, we perform a line-of-sight computation of the all-sky kSZ power spectrum and find that at large angular scales (l < 10), the local bulk flow should leave a visible signature above the Poisson-like fluctuations dominant at smaller scales, while the coupling of density and velocity fluctuations should give a much smaller contribution. We conduct an analysis of the prospects of future high-resolution CMB experiments (such as ACT and SPT) for detecting the kSZ signal and extracting cosmological information and dark energy constraints from it. We present two complementary methods, one suitable for "deep and narrow" surveys such as ACT and one suitable for "wide and shallow" surveys such as SPT. Both methods can constraint the equation of state of dark energy (w) to about 5%-10% when applied to forthcoming and future surveys and can probe w in complementary redshift ranges, which could shed some light on its time evolution. This is mainly due to the high sensitivity of the peculiar velocity field to the onset of the late acceleration of the universe. We stress that this determination of w does not rely on the knowledge of cluster masses, although it relies on cluster redshifts and makes minimal assumptions about cluster physics.