Modeling the kinematics of globular cluster systems
Modeling the kinematics of globular cluster systems
复制标题
球状星团系统的运动学建模
DOI：
10.1093/mnras/stac1651
复制
发表时间：
2022
影响因子：
4.8
通讯作者：
Gnedin, Oleg Y
中科院分区：
文献类型：
--
作者：
Chen, Yingtian;Gnedin, Oleg Y
球状星团(GC)是一种古老的大质量星团，是星系形成的“化石”。GAIA天文台的出现使我们能够对银河系GC进行详细的运动学研究，并彻底改变了我们对GC属性和星系组装之间关系的理解。然而，缺乏河外GC的运动学测量限制了我们能够充分研究的GC系统的样本量。在这项工作中，我们提出了一个GC形成和演化的模型，该模型通过在Illustris TNG50-1模拟中根据年龄和位置将单个GC分配给粒子来包含它们的位置和运动信息。我们利用银河系和河外GC系统的观测性质，包括位置分布、系统速度分布、速度色散分布、各向异性参数、轨道作用和金属度，对三个可调的模型参数进行了校准。我们还分析了不同来源的GC的性质。在外星系中，原星系团比原地形成的星系团更占优势。这导致GC金属活性从外到外降低，因为聚积的贫金属团簇的丰度越来越高。我们还发现，外星云具有更大的速度色散和轨道作用，这与它们的吸积起源是一致的。
Globular clusters (GCs) are old massive star clusters that serve as ‘fossils’ of galaxy formation. The advent ofGaiaobservatory 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 analyse the properties of GCs from different origins. In outer galaxy,ex situclusters are more dominant than the clusters formedin situ. This leads to the GC metallicities decreasing outwards due to the increasing abundance of accreted, metal-poor clusters. We also find theex-situGCs to have greater velocity dispersions and orbital actions, in agreement with their accretion origin.