Abstract We present new simulations of Lyman-α (Lyα) intensity maps that include Lyα radiative transfer in the intergalactic medium (IGM) and all significant sources of Lyα photons. The sources considered include Lyα directly from galaxies, cooling at the edges of ionized bubbles, recombinations within these bubbles, and reprocessing of galaxy continuum emission in the IGM. We also vary astrophysical parameters including the average neutral fraction of the IGM, the dust absorption of Lyα in galaxies, and the ionizing escape fraction. Previous work has suggested that Lyα intensity mapping can be used to constrain the neutral fraction of the IGM when accounting for radiative transfer in the IGM. When radiative transfer is ignored, direct Lyα emission from galaxies has the highest amplitude of power on all scales. When we include radiative transfer in our simulations, we find continuum emission reprocessed as Lyα is comparable to the Lyα emission directly from galaxies on large scales. For high neutral fraction in the IGM, emission from recombinations is comparable to galaxies on large scales. We find that the slope of the power spectrum is sensitive to the neutral fraction of the IGM when radiative transfer is included, suggesting that this may be useful for placing constraints on cosmic reionization. In addition, we find the power of galaxies is decreased across all scales due to dust absorption. We also find the escape fraction must be large for recombinations and bubble edges to contribute significantly to the power. We find the cross power is observable between SPHEREx Lyα intensity maps and a hypothetical galaxy survey is observable with a total signal-to-noise of 4 from k = 0.035 Mpc -1 to k = 1 Mpc -1 .
Ambrose et al. (Fri,) studied this question.