Extending the Epoch of Reionization window with apt Foreground and
  Instrument modeling
  It is seen that foregrounds of 21cm Epoch of Reionization experiments, which
are expected to have smooth spectral dependence, are dominant in a wedge shaped
region of the Fourier space called as Foreground Wedge. A possible way forward
to isolate the 21cm Epoch of Reionization (EoR) signal from the much larger
foreground component is to focus on the remaining portion of the Fourier space
called as the EoR window. There are in-fact three distinct regions in the
Fourier space, (i) the Foreground wedge portion, (ii) the EoR window region
which lies beyond Horizon wedge and (iii) the region in between the Horizon
wedge and the Field of View wedge. This paper addresses two questions: (1)
Whether the signal in between the two wedges is also a direct representation of
the EoR brightness temperature fluctuations? and (2) How can we extract the
cosmology information from this region considering that the foregrounds are
much larger than the signal? The answer to the first question is yes, the
visibilities as function of baseline and delay are, within a few percent, same
as the EoR brightness temperature fluctuations for the cases considered.
Secondly, the in between region is not foreground free, due to non-negligible
sidelobes. But, one can possibly extract signal from this region if one models
foregrounds and instruments accurately. As all the three components, the
cosmological signal, the foregrounds and the thermal noise are calculated in
the same space, the analysis suggested could be more straightforward.
