GASKAP-HI Pilot Survey Science III: An unbiased view of cold gas in the
  Small Magellanic Cloud
  We present the first unbiased survey of neutral hydrogen (HI) absorption in
the Small Magellanic Cloud (SMC). The survey utilises pilot HI observations
with the Australian Square Kilometre Array Pathfinder (ASKAP) telescope as part
of the Galactic ASKAP HI (GASKAP-HI) project whose dataset has been processed
with the GASKAP-HI absorption pipeline, also described here. This dataset
provides absorption spectra towards 229 continuum sources, a 275% increase in
the number of continuum sources previously published in the SMC region, as well
as an improvement in the quality of absorption spectra over previous surveys of
the SMC. Our unbiased view, combined with the closely matched beam size between
emission and absorption, reveals a lower cold gas faction (11%) than the 2019
ATCA survey of the SMC and is more representative of the SMC as a whole. We
also find that the optical depth varies greatly between the SMC's bar and wing
regions. In the bar we find that the optical depth is generally low (correction
factor to the optically thin column density assumption of $\mathcal{R}_{\rm HI}
\sim 1.04$) but increases linearly with column density. In the wing however,
there is a wide scatter in optical depth despite a tighter range of column
densities.
