Probing delayed-end reionization histories with the 21cm-LAE cross-power spectrum
Authors: Lewis Weinberger, Girish Kulkarni, Martin G Haehnelt
Journal: Monthly Notices of the Royal Astronomical Society, Volume 494, Issue 1, March 2020, Pages 703-718
Abstract: We model the 21-cm signal and LAE population evolution during the epoch of reionization in order to predict the 21cm-LAE cross-power spectrum. We employ high-dynamic-range simulations of the IGM to create models that are consistent with constraints from the CMB, Lyman-α forest and LAE population statistics. Using these models we consider the evolution of the cross-power spectrum for a selection of realistic reionization histories and predict the sensitivity of current and upcoming surveys to measuring this signal. We find that the imprint of a delayed-end to reionization can be observed by future surveys, and that strong constraints can be placed on the progression of reionization as late as z = 5.7 using a Subaru-SKA survey. We make predictions for the signal-to-noise ratios achievable by combinations of Subaru/PFS with the MWA, LOFAR, HERA and SKA interferometers for an integration time of 1000 hours. We find that a Subaru-SKA survey could measure the cross-power spectrum for a late reionization at z = 6.6 with a total signal-to-noise greater than 5, making it possible to constrain both the timing and bubble size at the end of reionization. Furthermore, we find that expanding the current Subaru/PFS survey area and depth by a factor of three would double the total signal-to-noise.