GASKAP-HI Pilot Survey Science I: ASKAP Zoom Observations of HI Emission
  in the Small Magellanic Cloud
  We present the most sensitive and detailed view of the neutral hydrogen (HI)
emission associated with the Small Magellanic Cloud (SMC), through the
combination of data from the Australian Square Kilometre Array Pathfinder
(ASKAP) and Parkes (Murriyang), as part of the Galactic Australian Square
Kilometre Array Pathfinder (GASKAP) pilot survey. These GASKAP-HI pilot
observations, for the first time, reveal HI in the SMC on similar physical
scales as other important tracers of the interstellar medium, such as molecular
gas and dust. The resultant image cube possesses an rms noise level of 1.1 K
(1.6 mJy/beam) per 0.98 km s$^{-1}$ spectral channel with an angular resolution
of 30$''$ ($\sim$10 pc). We discuss the calibration scheme and the custom
imaging pipeline that utilizes a joint deconvolution approach, efficiently
distributed across a computing cluster, to accurately recover the emission
extending across the entire $\sim$25 deg$^2$ field-of-view. We provide an
overview of the data products and characterize several aspects including the
noise properties as a function of angular resolution and the represented
spatial scales by deriving the global transfer function over the full spectral
range. A preliminary spatial power spectrum analysis on individual spectral
channels reveals that the power-law nature of the density distribution extends
down to scales of 10 pc. We highlight the scientific potential of these data by
comparing the properties of an outflowing high velocity cloud with previous
ASKAP+Parkes HI test observations.
