论文标题
Gaia-Sausage/Ecceladus的无混合碎片以一对光晕恒星过度的形式
The Unmixed Debris of Gaia-Sausage/Enceladus in the Form of a Pair of Halo Stellar Overdensities
论文作者
论文摘要
在成立后的头十亿年中，银河系与各种大众的矮人卫星进行了几次合并。负责银河系的最后一个重大合并的银河系盖亚苏斯/土卫（GSE）的碎片主导了内部光环，并被认为是大力神-aquila云（HAC）的祖细胞（HAC）和处女go的过度密度（VOD）。我们将SEGUE，Apogee，Gaia和Starhorse距离结合在一起，以表征化学动力学特性，并验证HAC，VOD和GSE之间的联系。我们发现，恒星过度和GSE的轨道偏心分布是可比的。我们还发现它们具有相似的，强烈的金属性分布函数，从而增强了共同起源的假设。此外，我们表明HAC和VOD与所分析的所有不含化学物质的空间中的原型GSE种群没有区别。所有这些证据结合在一起提供了一个明确的证明，即GSE合并是在这些光晕过度中发现的恒星种群的主要祖先。
In the first billion years after its formation, the Galaxy underwent several mergers with dwarf satellites of various masses. The debris of Gaia-Sausage/Enceladus (GSE), the galaxy responsible for the last significant merger of the Milky Way, dominates the inner halo and has been suggested to be the progenitor of both the Hercules-Aquila Cloud (HAC) and Virgo Overdensity (VOD). We combine SEGUE, APOGEE, Gaia, and StarHorse distances to characterize the chemodynamical properties and verify the link between HAC, VOD, and GSE. We find that the orbital eccentricity distributions of the stellar overdensities and GSE are comparable. We also find that they have similar, strongly peaked, metallicity distribution functions, reinforcing the hypothesis of common origin. Furthermore, we show that HAC and VOD are indistinguishable from the prototypical GSE population within all chemical-abundance spaces analyzed. All these evidences combined provide a clear demonstration that the GSE merger is the main progenitor of the stellar populations found within these halo overdensities.
