GASKAP-HI pilot survey science I: ASKAP zoom observations of Hi emission in the Small Magellanic Cloud. (7th February 2022)

• Record Type: Journal Article
• Authors: Pingel, N. M.; Dempsey, J.; McClure-Griffiths, N. M.; Dickey, J. M.; Jameson, K. E.; Arce, H.; Anglada, G.; Bland-Hawthorn, J.; Breen, S. L.; Buckland-Willis, F.; Clark, S. E.; Dawson, J. R.; Dénes, H.; Di Teodoro, E. M.; For, B.-Q.; Foster, Tyler J.; Gómez, J. F.; Imai, H.; Joncas, G.; Kim, C.-G.; Lee, M.-Y.; Lynn, C.; Leahy, D.; Ma, Y. K.; Marchal, A.; McConnell, D.; Miville-Deschènes, M.-A.; Moss, V. A.; Murray, C. E.; Nidever, D.; Peek, J.; Stanimirović, S.; Staveley-Smith, L.; Tepper-Garcia, T.; Tremblay, C. D.; Uscanga, L.; van Loon, J. Th.; Vázquez-Semadeni, E.; Allison, J. R.; Anderson, C. S.; Ball, Lewis; Bell, M.; Bock, D. C.-J.; Bunton, J.; Cooray, F. R.; Cornwell, T.; Koribalski, B. S.; Gupta, N.; Hayman, D. B.; Harvey-Smith, L.; Lee-Waddell, K.; Ng, A.; Phillips, C. J.; Voronkov, M.; Westmeier, T.; Whiting, M. T.;
• Is Part Of: Publications of the Astronomical Society of Australia. Volume 39(2022)
• Publication Date: 2022-02-07
• Subjects: Small Magellanic Cloud -- Hi line emission -- dwarf irregular galaxies -- interstellar medium; Astronomy -- Periodicals; Southern sky (Astronomy) -- Periodicals; Astrophysics -- Periodicals; Periodicals; 520.5
• DOI: 10.1017/pasa.2021.59
• Languages: English
• ISSNs: 1323-3580

Abstract

Abstract: We present the most sensitive and detailed view of the neutral hydrogen ( ${\rm H\small I}$ ) 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 ${\rm H\small I}$ 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 ( $1.6\, \mathrm{mJy\ beam}^{-1}$ ) $\mathrm{per}\ 0.98\, \mathrm{km\ s}^{-1}$ spectral channel with an angular resolution of $30^{\prime\prime}$ ( ${\sim}10\, \mathrm{pc}$ ). We discuss the calibration scheme and the custom imaging pipeline that utilises a joint deconvolution approach, efficiently distributed across a computing cluster, to accurately recover the emission extending across the entire ${\sim}25\, \mathrm{deg}^2$ field-of-view. We provide an overview of the data products and characterise 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 ${\rm H\small I}$ test observations.