The Effect of Foreground Mitigation Strategy on EoR Window Recovery
  The removal of the Galactic and extragalactic foregrounds remains a major
challenge for those wishing to make a detection of the Epoch of Reionization
21-cm signal. Multiple methods of modelling these foregrounds with varying
levels of assumption have been trialled and shown promising recoveries on
simulated data. Recently however there has been increased discussion of using
the expected shape of the foregrounds in Fourier space to define an EoR window
free of foreground contamination. By carrying out analysis within this window
only, one can avoid the foregrounds and any statistical bias they might
introduce by instead removing these foregrounds. In this paper we discuss the
advantages and disadvantages of both foreground removal and foreground
avoidance. We create a series of simulations with noise levels in line with
both current and future experiments and compare the recovered statistical
cosmological signal from foreground avoidance and a simplified, frequency
independent foreground removal model. We find that while, for current
generation experiments, foreground avoidance enables a better recovery at
$k_{perp} > 0.6 \mathrm{Mpc}^{-1}$, foreground removal is able to recover
significantly more signal at small $k_{los}$ for both current and future
experiments. We also relax the assumption that the foregrounds are smooth by
introducing a Gaussian random factor along the line-of-sight and then also
spatially. We find that both methods perform well for foreground models with
line-of-sight and spatial variations around $0.1\%$ however at levels larger
than this foregrounds removal shows a greater signal recovery.
