Identification of the long stellar stream of the prototypical massive globular cluster ω Centauri
Identification of the long stellar stream of the prototypical massive globular cluster ω Centauri
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DOI：
10.1038/s41550-019-0751-x
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发表时间：
2019-02
期刊：
影响因子：
14.1
通讯作者：
R. Ibata;M. Bellazzini;K. Malhan;N. Martin;P. Bianchini
中科院分区：
文献类型：
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作者：
R. Ibata;M. Bellazzini;K. Malhan;N. Martin;P. Bianchini
半人马座欧米茄 (ω Cen) 是银河系中质量最大的球状星团，长期以来一直被怀疑是吸积矮星系的残余核心。如果这种情况是正确的，则 ω Cen 应该受到潮汐限制，并且潮汐碎片应该沿着其轨道传播。在这里，我们使用 N 体模拟来表明，最近发现的“Fimbulthul”结构是人们长期寻找的 ω Cen 潮汐流，从星团延伸至 28°。五颗流星的后续高分辨率光谱表明，它们在速度上紧密分组，并且具有与起源于该星团一致的金属丰度。根据我们的 N 体模拟，我们设计了一个选择过滤器，应用于盖亚任务数据，以发现 ω Cen 10° 范围内高度污染和拥挤的区域中的流。对流的进一步建模可能有助于限制这个破坏系统的矮星系祖先的动力学历史，并指导未来在银河系中寻找其残余恒星。
Omega Centauri (ω Cen) is the Milky Way’s most massive globular cluster, and has long been suspected of being the remnant core of an accreted dwarf galaxy. If this scenario is correct, ω Cen should be tidally limited and tidal debris should be spread along its orbit. Here we useN-body simulations to show that the recently discovered ‘Fimbulthul’ structure is the long-sought-for tidal stream of ω Cen, extending up to 28° from the cluster. Follow-up high-resolution spectroscopy of five stream stars shows that they are closely grouped in velocity, and have metallicities consistent with having originated in that cluster. Informed by ourN-body simulations, we devise a selection filter that we apply to Gaia mission data to also uncover the stream in the highly contaminated and crowded field within 10° of ω Cen. Further modelling of the stream may help to constrain the dynamical history of the dwarf galaxy progenitor of this disrupting system and guide future searches for its remnant stars in the Milky Way.