SIMULATIONS OF THE MAGELLANIC STREAM IN A FIRST INFALL SCENARIO
SIMULATIONS OF THE MAGELLANIC STREAM IN A FIRST INFALL SCENARIO
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DOI：
10.1088/2041-8205/721/2/l97
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发表时间：
2010-08
期刊：
影响因子：
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通讯作者：
G. Besla;N. Kallivayalil;L. Hernquist;R. V. D. Marel;T. J. Cox;D. Keres̆
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文献类型：
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作者：
G. Besla;N. Kallivayalil;L. Hernquist;R. V. D. Marel;T. J. Cox;D. Keres̆
哈勃太空望远镜最近的高精度自行表明，大麦哲伦云和小麦哲伦云（分别为LMC和SMC）要么是第一次通过银河系，要么是在绕银河系（MW）的偏心长周期（>6 Gyr）轨道上。这与云在准周期轨道上运行的规范图像有明显的不同。如果没有一个短周期的轨道MW，麦哲伦流的起源，一个年轻的（1-2 Gyr老）相干流的氢气体，尾随云150°的天空，不能再归因于剥离MW潮汐和/或冲压压力剥离MW晕气体。我们提出了一种替代的形成机制，在该机制中，材料被删除的LMC潮汐作用于SMC之前，该系统是由MW吸积。我们证明了这种情况下使用N体/光滑粒子流体动力学模拟与宇宙学动机的初始条件约束的观测的可行性和一般性。在这些条件下，我们证明，它是可能的解释麦哲伦流的起源在第一次坠落的情况下。这张图片一般适用于任何富含气体的矮星系对，它们正朝着一个大质量的宿主坠落，或者孤立地相互作用。
Recent high-precision proper motions from the Hubble Space Telescope suggest that the Large and Small Magellanic Clouds (LMC and SMC, respectively) are either on their first passage or on an eccentric long period (>6 Gyr) orbit about the Milky Way (MW). This differs markedly from the canonical picture in which the Clouds travel on a quasi-periodic orbit about the MW (period of ∼2 Gyr). Without a short-period orbit about the MW, the origin of the Magellanic Stream, a young (1–2 Gyr old) coherent stream of H i gas that trails the Clouds ∼150° across the sky, can no longer be attributed to stripping by MW tides and/or ram pressure stripping by MW halo gas. We propose an alternative formation mechanism in which material is removed by LMC tides acting on the SMC before the system is accreted by the MW. We demonstrate the feasibility and generality of this scenario using an N-body/smoothed particle hydrodynamics simulation with cosmologically motivated initial conditions constrained by the observations. Under these conditions, we demonstrate that it is possible to explain the origin of the Magellanic Stream in a first infall scenario. This picture is generically applicable to any gas-rich dwarf galaxy pair infalling toward a massive host or interacting in isolation.