GASKAP-HI Pilot Survey Science I: ASKAP Zoom Observations of HI Emission in the Small Magellanic Cloud

Abstract

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${}^{\prime \prime }$ ($\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.

Accepted for publication in PASA, 34 pages, 18 figures, 5 tables

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Cited by in corpus (15)

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• Data Combination: Interferometry and Single-dish Imaging in Radio Astronomy
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• A new method for spatially resolving the turbulence driving mixture in the ISM with application to the Small Magellanic Cloud
• Peering into the Milky Way by FAST: I. Exquisite HI structures in the inner Galactic disk from the piggyback line observations of the FAST GPPS survey
• The Karl G. Jansky Very Large Array Local Group L-band Survey (LGLBS)
• HI filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments
• ATCA Study of Small Magellanic Cloud Supernova Remnant 1E 0102.2-7219
• Kinematics of stellar substructures in the Small Magellanic Cloud
• Cosmic Ray Feedback on Bi-stable ISM Turbulence
• The technological and scientific development of ASKAP
• A Galactic Transformation -- Understanding the SMC's Structural and Kinematic Disequilibrium
• A neutral hydrogen absorption study of cold gas in the outskirts of the Magellanic Clouds using the GASKAP-HI survey
• A Catalog of Stellar and Dust Properties for 500,000 Stars in the Southwest Bar of the Small Magellanic Cloud
• Processing of GASKAP-HI pilot survey data using a commercial supercomputer