Unbiased constraints on reionization model parameters in presence of the
  foreground wedge
  A possible way to disentangle the redshifted 21 cm signal of neutral hydrogen
(HI) in the Epoch of Reionization (EoR) from the much larger astrophysical
foregrounds is to restrict the analysis to a wedge-shaped region in the Fourier
space. The foregrounds are confined to this wedge because of their smooth
spectral properties which allows one to estimate the HI power spectrum in the
foreground-free portion, known as the reionization window. The estimate of the
spherically averaged power spectrum in the window, however, differs from the
true value because of the line of sight anisotropies in the signal. The
difference can be estimated and taken into account for a given reion- ization
model by expanding the power spectrum in terms of the Legendre polynomials.
This corrected power spectrum, called as the clustering wedges, can then be
used for comparing the model predictions with the observations. In this work,
we carefully ex- amine whether the clustering wedges are appropriate for such
model comparisons and whether they provide truly unbiased constraints on the
EoR parameters. We use the excursion-set based semi-numerical simulations,
coupled with MCMC-based statistical methods, for our analysis. We find that the
clustering wedges not only yield faithful constraints, the statistical
uncertainties on the parameter values too are comparable to those obtained
using the data without the presence of any foregrounds. We also find that the
clustering wedges are helpful in breaking the degeneracies between different
EoR model parameters.
