Realistic Simulations of the Galactic Polarized Foreground: Consequences
  for 21-cm Reionization Detection Experiments
  Experiments designed to measure the redshifted 21~cm line from the Epoch of
Reionization (EoR) are challenged by strong astrophysical foreground
contamination, ionospheric distortions, complex instrumental response and other
different types of noise (e.g. radio frequency interference). The astrophysical
foregrounds are dominated by diffuse synchrotron emission from our Galaxy. Here
we present a simulation of the Galactic emission used as a foreground module
for the LOFAR- EoR key science project end-to-end simulations. The simulation
produces total and polarized intensity over $10^\circ \times 10^\circ$ maps of
the Galactic synchrotron and free-free emission, including all observed
characteristics of the emission: spatial fluctuations of amplitude and spectral
index of the synchrotron emission, together with Faraday rotation effects. The
importance of these simulations arise from the fact that the Galactic polarized
emission could behave in a manner similar to the EoR signal along the frequency
direction. As a consequence, an improper instrumental calibration will give
rise to leakages of the polarized to the total signal and mask the desired EoR
signal. In this paper we address this for the first time through realistic
simulations.
