Signatures of minor mergers in the Milky Way disc – I. The SEGUE stellar sample
Signatures of minor mergers in the Milky Way disc – I. The SEGUE stellar sample
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DOI：
10.1111/j.1365-2966.2012.21176.x
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发表时间：
2012-01
影响因子：
4.8
通讯作者：
F. G'omez;I. Minchev;B. O’Shea;Y. S. Lee;T. Beers;D. An;J. Bullock;C. Purcell;'Alvaro Villalobos-'Al
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文献类型：
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作者：
F. G'omez;I. Minchev;B. O’Shea;Y. S. Lee;T. Beers;D. An;J. Bullock;C. Purcell;'Alvaro Villalobos-'Al
现在已经知道，较小的合并能够在其宿主星系盘的相空间分布中产生结构。为了在银河系中寻找这样的印记，我们分析了斯隆星系理解与探索扩展（SEGUE） F/G矮星和Schuster等恒星样本。我们在这两个完全独立的恒星样本中发现了类似的特征，与银河系小型合并事件的预测一致。接下来，我们将同样的分析应用于高分辨率，理想化的n体模拟人马座矮星系和银河系之间的相互作用。在宿主盘的小空间区域内，恒星粒子样品的能量分布显示出结构随位置的强烈变化。我们找到了与人马座暗物质晕祖先1011m⊙质量模型的观测结果很好的匹配。因此，我们表明，这种分析可以用来对人马座的轨道参数提供前所未有的严格约束，以及对其质量的下限。
It is now known that minor mergers are capable of creating structure in the phase-space distribution of their host galaxy’s disc. In order to search for such imprints in the Milky Way, we analyse the Sloan Extension for Galactic Understanding and Exploration (SEGUE) F/G dwarf and the Schuster et al. stellar samples. We find similar features in these two completely independent stellar samples, consistent with the predictions of a Milky Way minor-merger event. We next apply the same analyses to high-resolution, idealized N-body simulations of the interaction between the Sagittarius dwarf galaxy and the Milky Way. The energy distributions of stellar particle samples in small spatial regions in the host disc reveal strong variations of structure with position. We find good matches to the observations for models with a mass of Sagittarius’ dark matter halo progenitor 1011 M⊙. Thus, we show that this kind of analysis could be used to provide unprecedentedly tight constraints on Sagittarius’ orbital parameters, as well as place a lower limit on its mass.