Is the dark matter halo of the Milky Way flattened
Is the dark matter halo of the Milky Way flattened
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银河系暗物质晕变平了吗
DOI：
10.1051/0004-6361:20065538
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Christian Theis
中科院分区：
文献类型：
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作者：
A. Růžička;J. Palouš;Christian Theis
我们进行了一个扩展的分析参数空间的相互作用的麦哲伦星系与银河系（MW）。变化的参数包括相空间参数，质量，结构和方向的麦哲伦云，以及平坦的暗物质晕MW。通过专门采用的优化代码进行分析，以搜索数值模型与Bruns等人（2005，A&A，432，45）的麦哲伦系统的详细H I图之间的最佳匹配。应用的搜索算法是一种遗传算法结合的代码的基础上快速，但近似的限制Nbody方法。通过这一点，我们能够分析超过106个模型，这使得这项研究成为麦哲伦系统最广泛的研究之一。在这里，我们集中在轴对称MW暗物质晕势的平坦化q，这是在0.74 ≤ q ≤ 1.20范围内研究。我们发现，创建一个拖尾（麦哲伦流）和领先的流（领先的手臂）是一个相当常见的功能的麦哲伦系统MW相互作用，这样的结构在整个范围内的晕平坦值建模。然而，重要的差异之间存在的模型，关于密度分布和运动学的H I，也麦哲伦系统的动力学演化。对中性氢分布的模拟结果与观测结果之间总体一致性的详细分析表明，假设银河系暗物质晕为扁圆形（q < 1.0）的模型比具有其他晕结构的模型更能满足H I观测结果。
We performed an extended analysis of the parameter space for the interaction of the Magellanic System with the Milky Way (MW). The varied parameters cover the phase space parameters, the masses, the structure, and the orientation of both Magellanic Clouds, as well as the flattening of the dark matter halo of the MW. The analysis was done by a specially adopted optimization code searching for the best match between numerical models and the detailed H I map of the Magellanic System by Bruns et al. (2005, A&A, 432, 45). The applied search algorithm is a genetic algorithm combined with a code based on the fast, but approximative restricted Nbody method. By this, we were able to analyze more than 106 models, which makes this study one of the most extended ones for the Magellanic System. Here we focus on the flattening q of the axially symmetric MW dark matter halo potential, that is studied within the range 0.74 ≤ q ≤ 1.20. We show that creation of a trailing tail (Magellanic Stream) and a leading stream (Leading Arm) is quite a common feature of the Magellanic System-MW interaction, and such structures were modeled across the entire range of halo flattening values. However, important differences exist between the models, concerning density distribution and kinematics of H I, and also the dynamical evolution of the Magellanic System. Detailed analysis of the overall agreement between modeled and observed distribution of neutral hydrogen shows that the models assuming an oblate (q < 1.0) dark matter halo of the Galaxy allow for better satisfaction of H I observations than models with other halo configurations.