Probing delayed-end reionization histories with the 21cm-LAE cross-power
  spectrum
  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-$\alpha$ 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.
