论文标题
与{\ textit {gaia}} DR2 Astrometrymergementrymermotery一起寻找银河球体群体NGC 2808，NGC 6266和NGC 6397周围的临时候选候选者的搜索。
The search for extratidal star candidates around Galactic globular clusters NGC 2808, NGC 6266, and NGC 6397 with {\textit{Gaia}} DR2 astrometry
论文作者
论文摘要
语境。外星是恒星体，由于内部过程或作用在其上的外力而导致簇的潮汐半径之外。这些恒星的存在和空间分布可以使我们了解银河系中聚类的过去演变。目标。先前的作品表明，当详细探讨球状簇时，显示出牙外恒星的证据。我们旨在使用GAIA DR2数据库的光度法和适当的运动测量（Gaia Collaboration et al.2018），在银河球状簇NGC 6397，NGC 2808和NGC 6266中寻找可能的外恒星。结果。最后，分别在球状簇NGC 6397，NGC 2808和NGC 6266的潮汐半径外发现了120、126和107个外候选恒星。发现的70％，25.4％和72.9％的恒星分别位于NGC 6397，NGC 2808和NGC 6266的Jacobi半径之外。属于NGC 6397的外恒星的空间分布似乎是S的，沿弯曲的前导和后臂延伸。 NGC 2808在集群的尾随部分中具有过度密度，而NGC 6266似乎在其东部和北侧有过度的恒星。结论。适当的运动和色彩图可用于识别GC周围周围的候选恒星。尽管如此，根据将簇的运动学和恒星种群与银河系场进行比较的不同，污染的比例可能更大。发现所有三个簇都在其潮汐半径之外具有外星。对于NGC 6397和NGC 2808，这些恒星可能是圆盘冲击和潮汐破坏的综合作用的结果。对于NGC 6266，周围恒星的分布在其周围是对称的，很可能表明该簇具有扩展的恒星包膜。
Context. Extratidal stars are stellar bodies that end up outside the tidal radius of a cluster as a result of internal processes or external forces acting upon it. The presence and spatial distribution of these stars can give us insights into the past evolution of a cluster inside our Galaxy. Aims. Previous works suggest that globular clusters, when explored in detail, show evidence of extratidal stars. We aim to search for possible extratidal stars in the Galactic globular clusters NGC 6397, NGC 2808, and NGC 6266 using the photometry and proper motion measurements from Gaia DR2 database (Gaia Collaboration et al. 2018). Results. Finally, 120, 126, and 107 extratidal candidate stars were found lying outside the tidal radius of the globular clusters NGC 6397, NGC 2808, and NGC 6266, respectively. 70%, 25.4%, and 72.9% of the extratidal stars found are located outside the Jacobi radius of NGC 6397, NGC 2808, and NGC 6266, respectively. The spatial distribution of the extratidal stars belonging to NGC 6397 appears S-like, extending along the curved leading and trailing arms. NGC 2808 has an overdensity of stars in the trailing part of the cluster and NGC 6266 seems to have overdensities of extratidal stars in its eastern and northern sides. Conclusions. Proper motions and color-magnitude diagrams can be used to identify extratidal candidate stars around GCs. Nonetheless, depending on how different the kinematics and stellar populations of a cluster are compared to the Milky Way field, the fraction of contamination can be larger. All three clusters are found to have extratidal stars outside their tidal radii. For NGC 6397 and NGC 2808, these stars may be the result of a combined effect of the disc shocks and tidal disruptions. For NGC 6266, the distribution of extratidal stars is symmetrical around it, most likely indicating that the cluster has an extended stellar envelope.
