THE KINETIC SUNYAEV–ZEL’DOVICH EFFECT FROM REIONIZATION: SIMULATED FULL-SKY MAPS AT ARCMINUTE RESOLUTION

Abstract

The kinetic Sunyaev–Zel’dovich (kSZ) effect results from Thomson scattering by coherent flows in the reionized intergalactic medium. We present new results based on ray-tracing an 8 Gpc/ h realization of reionization with resolution elements 2 Mpc/ h (subtending ′ at z = 6) on a side to create a full-sky kSZ map. The realization includes, self-consistently, the effects of reionization on scales corresponding to multipoles . We separate the kSZ map into Doppler ( ), Ostriker–Vishniac ( ), patchy ( ), and third-order ( ) components, and compute explicitly all the auto- and cross-correlations (e.g., , , etc.) that contribute to the total power. We find a complex and nonmonotonic dependence on the duration of reionization at and evidence for a non-negligible (10%–30%) contribution from connected four-point correlations, , usually neglected in analytical models. We also investigate the cross-correlation of linear matter and large-scale kSZ temperature fluctuations, focusing on (1) cross-power spectra with biased tracers of the matter density and (2) cold spots from infall onto large, rare H ii regions centered on peaks in the matter distribution at redshifts that are a generic non-Gaussian feature of patchy reionization. Finally, we show that the reionization history can be reconstructed at 5 σ –10 σ significance by correlating full-sky 21 cm maps stacked in bins with with existing cosmic microwave background (CMB) temperature maps at , raising the prospects for probing reionization by correlating CMB and LSS measurements. The resulting kSZ maps have been made publicly available at www.cita.utoronto.ca/~malvarez/research/ksz-data/ .