论文标题
银河系的积聚核簇
The Accreted Nuclear Clusters of the Milky Way
论文作者
论文摘要
银河系中的光环，凸起和圆盘中的许多大型簇不是真正的球状簇（GC），而是完全不同的野兽。自从银河系吸收以来，它们是古代星系的残余核星簇（NSC）。尽管有些集群很容易被识别为NSC，并且可以很容易地追溯到他们的主机银河系（例如M54和Sagittarius矮人银河系），而其他群集则证明更难以捉摸。在这里，我们结合了许多独立的约束，着重于它们的内部丰度和整体运动学，以找到由银河系吸收的NSC，并将其追溯到其积聚事件。我们发现，由Galaxy积累的真正NSC是：M54来自Sagittarius Dwarf，$ω$ CENTARI，来自Gaia-cenceladus/Sausage，NGC 6273，来自Kraken和（潜在的）NGC 6934，来自Helmi Streams。这些NSC是搜索星形簇中中间质量黑洞（BHS）的主要候选者，鉴于托有NSC和中央大型BHS的星系的常见发生。 NSC似乎没有与红杉或其他次要积聚事件有关。其他声称的NSC被证明不是这样。我们还讨论了Terzan 5的特殊情况，这可能代表了集群集群合并的独特情况。
A number of the massive clusters in the halo, bulge and disc of the Galaxy are not genuine globular clusters (GCs), but instead are different beasts altogether. They are the remnant nuclear star clusters (NSCs) of ancient galaxies since accreted by the Milky Way. While some clusters are readily identifiable as NSCs, and can be readily traced back to their host galaxy (e.g., M54 and the Sagittarius Dwarf galaxy) others have proven more elusive. Here we combine a number of independent constraints, focusing on their internal abundances and overall kinematics, to find NSCs accreted by the Galaxy and trace them to their accretion event. We find that the true NSCs accreted by the Galaxy are: M54 from the Sagittarius Dwarf, $ω$ Centari from Gaia-Enceladus/Sausage, NGC 6273 from Kraken and (potentially) NGC 6934 from the Helmi Streams. These NSCs are prime candidates for searches of intermediate mass black holes (BHs) within star clusters, given the common occurrence of galaxies hosting both NSCs and central massive BHs. No NSC appears to be associated with Sequoia or other minor accretion events. Other claimed NSCs are shown not to be such. We also discuss the peculiar case of Terzan 5, which may represent a unique case of a cluster-cluster merger.
