Signatures of Cosmic Reionization on the 21cm 3-Point Correlation
Constraints on reionization models from future 21cm observations will rely
on the statistical characterization of the spatial fluctuations in the
observed 21cm brightness temperature. So far studies have focused almost
exclusively on second-order statistics, such as 2-point correlations,
to characterize these fluctuations, neglecting a significant amount of
information, which is encoded in the higher-order statistics. I will
present a study of the 21cm 3-point correlation in configuration space,
as predicted by a semi-numerical simulation. The results show a strong
dependence of the 3-point correlation on the triangle shape, as
we probe the morphology of large-scale fluctuations in the 21cm signal.
This behavior changes strongly for different reionization
scenarios and can hence be used to tighten observational constraints
from the 2-point correlation on the latter.
I will further discuss a physical interpretation
of 21cm correlations during reionization in terms of the local
quadratic bias model as well a simple approach for generating fast
predictions for 21cm observations using random walks.