论文标题
建模球状簇系统的运动学
Modeling the kinematics of globular cluster systems
论文作者
论文摘要
球形簇(GC)是旧的巨大恒星簇,用作银河系的“化石”。盖亚天文台的出现使银河GC的详细运动学研究彻底改变了我们对GC属性与星系组装之间联系的理解。然而,缺乏对乳突外GC的运动学测量限制了我们可以完全研究的GC系统的样本量。在这项工作中,我们提出了一个用于GC形成和进化的模型,其中包括单个GC的位置和运动学信息,通过将它们分配给基于年龄和位置的Illustris TNG50-1模拟中的粒子。我们使用银河系和阿加拉术GC系统的观察性特性来校准这三个可调模型参数,包括位置的分布,系统速度,速度分散,各向异性参数,轨道作用和金属性。我们还分析了来自不同起源的GC的性质。在外星系中,前坐骨簇比在原位形成的群集更为主导。这会导致GC金属度降低,这是由于增强的金属贫困簇的丰度增加。我们还发现,与其积聚起源一致,前态GC具有更大的速度分散和轨道作用。
Globular clusters (GCs) are old massive star clusters that serve as `fossils' of galaxy formation. The advent of Gaia observatory has enabled detailed kinematics studies of the Galactic GCs and revolutionized our understanding of the connections between GC properties and galaxy assembly. However, lack of kinematic measurements of extragalactic GCs limits the sample size of GC systems that we can fully study. In this work, we present a model for GC formation and evolution, which includes positional and kinematic information of individual GCs by assigning them to particles in the Illustris TNG50-1 simulation based on age and location. We calibrate the three adjustable model parameters using observed properties of the Galactic and extragalactic GC systems, including the distributions of position, systemic velocity, velocity dispersion, anisotropy parameter, orbital actions, and metallicities. We also analyze the properties of GCs from different origins. In outer galaxy, ex-situ clusters are more dominant than the clusters formed in-situ. This leads to the GC metallicities decreasing outwards due to the increasing abundance of accreted, metal-poor clusters. We also find the ex-situ GCs to have greater velocity dispersions and orbital actions, in agreement with their accretion origin.