论文标题
Lamost调查中具有香肠运动学的低α金属恒星：它们是来自Gaia-Sausage-cenceladus Galaxy吗？
Low-alpha Metal-Rich Stars with Sausage Kinematics in the LAMOST Survey: Are they from the Gaia-Sausage-Enceladus Galaxy?
论文作者
论文摘要
我们在Lamost DR5中搜索具有[Fe/H]> -0.8和-100 <VPHI <50 km/s的富含金属的香肠 - 基因化（MRSK）恒星，以研究Gaia-Sausage-cenceladus（GSE）合并事件在Galactic Disk上的影响。我们第一次找到一组低αMRSK星，并根据化学和运动学特性将其归类为GSE星系的富含金属尾巴。该组的RAPO，ZMAX和ETOT分布略大于先前报告的高α组。它的低α比率不允许由GSE合并事件的飞溅过程产生的来源，正如提出的解释高α群体所提出的那样。 Amarante等人的流体动力学模拟。提供了一种有希望的解决方案，其中GSE Galaxy是一种笨拙的乳白色类似物，形成了双峰磁盘化学。这种情况解释了这项工作中发现高α和低α比的MRSK恒星的存在。另一个新功能进一步支持了MRSK星团位于Zmax = 3-5 kpc，这对应于| z | 〜4 kpc的广泛采用的磁盘旋转过渡。我们建议，Zmax的MRSK星星堆积对这种磁盘过渡产生了重大贡献，这是GSE合并事件留下的有趣的烙印。这些结果还为GSE与处女座径向合并之间的联系提供了重要的含义。
We search for metal-rich Sausage-kinematic (MRSK) stars with [Fe/H]> -0.8 and -100<Vphi<50 km/s in LAMOST DR5 in order to investigate the influence of the Gaia-Sausage-Enceladus (GSE) merger event on the Galactic disk. For the first time, we find a group of low-alpha MRSK stars, and classify it as a metal-rich tail of the GSE galaxy based on the chemical and kinematical properties. This group has slightly larger Rapo, Zmax and Etot distributions than a previously-reported high-alpha group. Its low-alpha ratio does not allow for an origin resulting from the splash process of the GSE merger event, as is proposed to explain the high-alpha group. A hydrodynamical simulation by Amarante et al. provides a promising solution, in which the GSE galaxy is a clumpy Milky-Way analogue that develops a bimodal disk chemistry. This scenario explains the existence of MRSK stars with both high-alpha and low-alpha ratios found in this work. It is further supported by another new feature that a clump of MRSK stars is located at Zmax=3-5 kpc, which corresponds to the widely adopted disk-halo transition at |Z|~4 kpc. We suggest that a pile-up of MRSK stars at Zmax contributes significantly to this disk-halo transition, an interesting imprint left by the GSE merger event. These results also provide an important implication on the connection between the GSE and the Virgo Radial Merger.
