Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by S 5
Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by S 5
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DOI：
10.3847/1538-4357/ac2e93
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发表时间：
2021-07
期刊：
影响因子：
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通讯作者：
N. Shipp;D. Erkal;A. Drlica-Wagner;Ting S. Li;A. Pace;Sergey E. Koposov;L. Cullinane;G. Costa;A. Ji;K. Kuehn;G. Lewis;D. Mackey;J. Simpson;Z. Wan;D. Zucker;J. Bland-Hawthorn;P. Ferguson;Sophia Lilleengen;Sdss Collaboration
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文献类型：
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作者：
N. Shipp;D. Erkal;A. Drlica-Wagner;Ting S. Li;A. Pace;Sergey E. Koposov;L. Cullinane;G. Costa;A. Ji;K. Kuehn;G. Lewis;D. Mackey;J. Simpson;Z. Wan;D. Zucker;J. Bland-Hawthorn;P. Ferguson;Sophia Lilleengen;Sdss Collaboration
恒星流是探测它们演化的潜在引力势的极佳探测器。在这项工作中，我们将动力学模型拟合到南银河半球的五个星流，结合来自南方恒星流谱巡天(S 5)、Gaia EDR3和暗能量调查的观测，测量了大麦哲伦云(LMC)的质量。对于一组流团，我们发现了从∼14-19×1010M⊙的质量，探测范围是最近的接近时间和距离。对于最受约束的溪流(孤儿-Chenab)，我们测量到的LMC质量为18.8kpc+3.5×1010m−，最接近时间为310Myr，最近接近距离为25.4kpC。这一质量与之前的测量结果是一致的，表明LMC对银河系结构的影响正在形成一致的图景。使用这一流的样本，我们发现LMC的效果取决于流和LMC在其最接近点的相对方向。为了更好地理解这一点，我们提出了一个基于脉冲近似的简单模型，并证明了LMC的影响既取决于赋予水流的速度冲击的大小，也取决于该冲击的方向。
Stellar streams are excellent probes of the underlying gravitational potential in which they evolve. In this work, we fit dynamical models to five streams in the Southern Galactic hemisphere, combining observations from the Southern Stellar Stream Spectroscopic Survey (S 5), Gaia EDR3, and the Dark Energy Survey, to measure the mass of the Large Magellanic Cloud (LMC). With an ensemble of streams, we find a mass of the LMC ranging from ∼14–19 × 1010 M ⊙, probed over a range of closest approach times and distances. With the most constraining stream (Orphan–Chenab), we measure an LMC mass of 18.8−4.0+3.5×1010M⊙ , probed at a closest approach time of 310 Myr and a closest approach distance of 25.4 kpc. This mass is compatible with previous measurements, showing that a consistent picture is emerging of the LMC’s influence on structures in the Milky Way. Using this sample of streams, we find that the LMC’s effect depends on the relative orientation of the stream and LMC at their point of closest approach. To better understand this, we present a simple model based on the impulse approximation and we show that the LMC’s effect depends both on the magnitude of the velocity kick imparted to the stream and the direction of this kick.