The 3D Kinematics of Gas in the Small Magellanic Cloud
Date
2019
Authors
Murray, Claire E.
Peek, J. E. G.
Di Teodoro, Enrico
McClure-Griffiths, Naomi
Dickey, John
D'nes, Helga
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Volume Title
Publisher
IOP Publishing
Abstract
We investigate the kinematics of neutral gas in the Small Magellanic Cloud (SMC) and test the hypothesis that it is
rotating in a disk. To trace the 3D motions of the neutral gas distribution, we identify a sample of young, massive
stars embedded within it. These are stars with radial velocity measurements from spectroscopic surveys and proper
motion measurements from Gaia, whose radial velocities match with dominant H I components. We compare the
observed radial and tangential velocities of these stars with predictions from the state-of-the-art rotating disk model
based on high-resolution 21 cm observations of the SMC from the Australian Square Kilometer Array Pathfinder
telescope. We find that the observed kinematics of gas-tracing stars are inconsistent with disk rotation. We
conclude that the kinematics of gas in the SMC are more complex than can be inferred from the integrated radial
velocity field. As a result of violent tidal interactions with the Large Magellanic Cloud, nonrotational motions are
prevalent throughout the SMC, and it is likely composed of distinct substructures overlapping along the line of
sight.
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The Astrophysical Journal
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Journal article
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Open Access
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