The 3D Kinematics of Gas in the Small Magellanic Cloud
The 3D Kinematics of Gas in the Small Magellanic Cloud
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DOI：
10.3847/1538-4357/ab510f
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发表时间：
2019-10
期刊：
影响因子：
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通讯作者：
C. Murray;J. Peek;E. D. Teodoro;N. McClure-Griffiths;J. Dickey;H. Dénes
中科院分区：
文献类型：
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作者：
C. Murray;J. Peek;E. D. Teodoro;N. McClure-Griffiths;J. Dickey;H. Dénes
我们研究了小麦哲伦云（SMC）中中性气体的运动学，并检验了它在圆盘中旋转的假设。为了追踪中性气体分布的3D运动，我们确定了一个年轻的大质量恒星样本，这些恒星的径向速度测量来自光谱测量和盖亚的自行测量，其径向速度与占主导地位的H i分量相匹配。我们比较观察到的径向和切向速度，这些恒星的预测从国家的最先进的旋转盘模型的基础上高分辨率21厘米的观测SMC从澳大利亚平方公里阵列探路者望远镜。我们发现，观测到的气体示踪星的运动学是不一致的磁盘旋转。我们的结论是，SMC中的气体的运动学比可以推断出的集成径向速度场更复杂。由于大麦哲伦云与潮汐的剧烈相互作用，非旋转运动在整个SMC中普遍存在，它很可能由沿着视线重叠的不同子结构组成。
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.