Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud
Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud
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DOI：
10.3847/1538-4357/ac5621
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发表时间：
2022-02
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通讯作者：
Xinlun Cheng;Yumi Choi;K. Olsen;D. Nidever;S. Majewski;A. Monachesi;G. Besla;César Muñoz Gonzalez;B. Anguiano;Andr'es Almeida;R. Muñoz;R. Lane;C. Nitschelm
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作者：
Xinlun Cheng;Yumi Choi;K. Olsen;D. Nidever;S. Majewski;A. Monachesi;G. Besla;César Muñoz Gonzalez;B. Anguiano;Andr'es Almeida;R. Muñoz;R. Lane;C. Nitschelm
我们报告的第一个3D运动学测量的88颗恒星的几个最近发现的子结构的方向在南部外围的大麦哲伦星云（LMC）使用组合的盖亚自行和径向速度的APOGEE-2调查。更具体地说，我们探索恒星在各种APOGEE-2点在LMC周边地区的各种overdensity的恒星以前已被确定在地图上的恒星从盖亚和DECam。通过使用一个模型的LMC磁盘旋转，我们发现，相当大的一部分的APOGEE-2恒星具有极端的空间速度是不同的，而不是一个简单的扩展，LMC磁盘。使用N-体流体动力学模拟过去的动力学演化和相互作用的LMC和小麦哲伦云（SMC），我们探讨是否极端速度的恒星可以占在这个过程中产生的潮汐碎片的相互作用。我们的结论是，LMC和SMC碎片从他们的相互作用产生的组合是一个很有前途的解释，虽然我们不能排除其他可能的起源，这些新的数据应用于约束未来的模拟LMC-SMC相互作用。我们还得出结论，大麦哲伦星云南部边缘的许多恒星位于大麦哲伦星云平面之外，距离大麦哲伦星云平面有几千秒差距。考虑到这些恒星的金属丰度表明它们可能是麦哲伦起源的，我们的研究结果表明，需要对麦哲伦云过去的相互作用历史进行更广泛的探索。
We report the first 3D kinematical measurements of 88 stars in the direction of several recently discovered substructures in the southern periphery of the Large Magellanic Cloud (LMC) using a combination of Gaia proper motions and radial velocities from the APOGEE-2 survey. More specifically, we explore stars in assorted APOGEE-2 pointings in a region of the LMC periphery where various overdensities of stars have previously been identified in maps of stars from Gaia and DECam. By using a model of the LMC disk rotation, we find that a sizable fraction of the APOGEE-2 stars have extreme space velocities that are distinct from, and not a simple extension of, the LMC disk. Using N-body hydrodynamical simulations of the past dynamical evolution and interaction of the LMC and Small Magellanic Cloud (SMC), we explore whether the extreme-velocity stars may be accounted for as tidal debris created in the course of that interaction. We conclude that the combination of LMC and SMC debris produced from their interaction is a promising explanation, although we cannot rule out other possible origins, and that these new data should be used to constrain future simulations of the LMC–SMC interaction. We also conclude that many of the stars in the southern periphery of the LMC lie outside of the LMC plane by several kiloparsecs. Given that the metallicity of these stars suggests that they are likely of Magellanic origin, our results suggest that a wider exploration of the past interaction history of the Magellanic Clouds is needed.