August 6, 2018Open Access
The Impact of Neutral Intergalactic Gas on Lyα Intensity Mapping during Reionization
Key Points
Key points are not available for this paper at this time.
Abstract
Abstract We present the first simulations of the high-redshift Ly α intensity field that account for scattering in the intergalactic medium (IGM). Using a 3D Monte Carlo radiative transfer code, we find that Ly α scattering smooths spatial fluctuations in the Ly α intensity on small scales, and that the spatial dependence of this smoothing depends on the mean neutral fraction of the IGM. Our simulations find a strong effect of reionization on k = 0.1–1 Mpc −1 , with for and for , in contrast to after reionization. At wavenumbers of k > 1 Mpc −1 , we find that the signal is sensitive to the emergent Ly α line profiles from galaxies. We also demonstrate that the cross-correlation between a Ly α intensity map and a future galaxy redshift survey could be detected on large scales by an instrument similar to SPHEREx , and over a wide range of scales by a hypothetical intensity mapping instrument in the vein of the Cosmic Dawn Intensity Mapper ( CDIM ).