Redshift-space distortions in simulations of the 21-cm signal from the
  cosmic dawn
  The 21-cm signal from the Cosmic Dawn (CD) is likely to contain large
fluctuations, with the most extreme astrophysical models on the verge of being
ruled out by observations from radio interferometers. It is therefore vital
that we understand not only the astrophysical processes governing this signal,
but also other inherent processes impacting the signal itself, and in
particular line-of-sight effects. Using our suite of fully numerical radiative
transfer simulations, we investigate the impact on the redshifted 21-cm from
the CD from one of these processes, namely the redshift-space distortions
(RSDs). When RSDs are added, the resulting boost to the power spectra makes the
signal more detectable for our models at all redshifts, further strengthening
hopes that a power spectra measurement of the CD will be possible. RSDs lead to
anisotropy in the signal at the beginning and end of the CD, but not while
X-ray heating is underway. The inclusion of RSDs, however, decreases
detectability of the non-Gaussianity of fluctuations from inhomogeneous X-ray
heating measured by the skewness and kurtosis. On the other hand, mock
observations created from all our simulations that include telescope noise
corresponding to 1000 h observation with the Square Kilometre Array telescope
show that we may be able image the CD for all heating models considered and
suggest RSDs dramatically boost fluctuations coming from the inhomogeneous
Ly-$\alpha$ background.
