http://arxiv.org/abs/1511.02846
The kinetic Sunyaev-Zel’dovich (kSZ) effect results from Thomson scattering by coherent flows the reionized intergalactic medium. The new results presented here follow from ray-tracing a 10 Gpc scale simulations at 2-3 Mpc scale resolution to create a full sky kSZ map that self-consistently includes the effects of reionization on scales corresponding to multipoles $10\lesssim\ell\lesssim{5000}$. We separate the kSZ map into Doppler ($\mathbf{v}$), Ostriker-Vishniac ($\delta\mathbf{v}$), patchy ($x\mathbf{v}$), and third-order ($x\delta\mathbf{v}$) components, and compute explicitly all the auto and cross correlations (e.g., $\langle\mathbf{v}\mathbf{v}\rangle$, $\langle\delta\mathbf{v}{x}\mathbf{v}\rangle$, etc.) that contribute to the total power. We find a complex and non-monotonic dependence on the duration of reionization at $\ell\sim{300}$ and evidence for a non-negligible (10-30 per cent) contribution from connected four point ionization-velocity correlations, $\langle{x}\mathbf{v}x\mathbf{v}\rangle_c$, that are usually neglected in analytical models. We also investigate the Doppler-large scale structure (LSS) correlation, focusing on two different probes: (1) cross power spectra with linearly biased tracers of LSS and (2) cold spots from infall onto large, rare \ion{H}{2} regions centered on peaks in the matter distribution at redshifts $z>10$ that are a generic non-Gaussian feature induced by patchy reionization. Finally, we use our simulations to show that the reionization history can be reconstructed at 5-10$\sigma$ significance by correlating full-sky 21-cm maps stacked in bins with $\Delta\nu\!=\!10$ MHz with existing CMB temperature maps at $\ell<500$.This raises the prospects of using more sophisticated velocity reconstruction methods to probe the distribution of electrons in the IGM by using combined CMB and LSS measurements well into the epoch of reionization.
M. Alvarez
Tue, 10 Nov 15
2/62
Comments: 15 pages, 11 figures, comments welcome. High resolution figures available this http URL
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