论文标题
与光环中的球状簇对相关的低质量恒星植物流
A Low-Mass Stellar-Debris Stream Associated with a Globular Cluster Pair in the Halo
论文作者
论文摘要
预计将以银河系的方式与球状簇（GC）和恒星子结构之间存在物理关系，尚未找到所有这些子结构。我们从SDSS蓝色水平分支和SDSS+Lamost RR Lyrae星的组合光环样本中搜索此类子结构，并与$ Gaia $ dr2的Astrestric信息交叉匹配。这是一个旧星星的样本，它们也是结构的出色示踪剂，非常适合在外部恒星光环中寻找古代文物。通过将基于神经网络的方法应用于样品的整个4D动力空间，我们重新发现了射手座流，并找到$ GAIA $ -ENCELADUS-SAUSAGE（GES）的碎屑（GES）和Outer Halo中的红杉事件，以及与几个GC的链接。最重要的是，我们找到了与一对GC（NGC 5024和NGC 5053）相关的新的低质量碎屑流，我们将其列为LMS-1。该流具有非常极性的轨道，并且占据了距银河中心10至20 kpc的区域。 NGC 5024（M53）是相关GC对的更大的质量，很可能是基于N体模拟的结果，这是现已中断的矮星状祖细胞的核星簇。
There are expected to be physical relationships between the globular clusters (GCs) and stellar substructures in the Milky Way, not all of which have yet been found. We search for such substructures from a combined halo sample of SDSS blue horizontal-branch and SDSS+LAMOST RR Lyrae stars, cross-matched with astrometric information from $Gaia$ DR2. This is a sample of old stars which are also excellent tracers of structures, ideal for searching for ancient relics in the outer stellar halo. By applying the neural-network-based method StarGO to the full 4D dynamical space of our sample, we rediscover the Sagittarius Stream, and find the debris of the $Gaia$-Enceladus-Sausage (GES) and the Sequoia events in the outer halo, as well as their linkages with several GCs. Most importantly, we find a new, low-mass, debris stream associated with a pair of GCs (NGC 5024 and NGC 5053), which we dub LMS-1. This stream has a very polar orbit, and occupies a region between 10 to 20 kpc from the Galactic center. NGC 5024 (M53), the more-massive of the associated GC pair, is very likely the nuclear star cluster of a now-disrupted dwarf galaxy progenitor, based on the results from N-body simulations.
