论文标题
GAIA EDR3和HUBBLE空间望远镜的大型麦哲伦云球形集群系统的运动学结构适当运动
Kinematic Structure of the Large Magellanic Cloud Globular Cluster System from Gaia eDR3 and Hubble Space Telescope Proper Motions
论文作者
论文摘要
我们使用多个独立的分析技术确定了GAIA EDR3和Hubble空间望远镜数据的31个LMC GC的批量正确运动（PMS）。结合距离，视线速度和现有散装PM的文献值，我们为32个簇提取完整的6D相空间信息，使我们能够详细检查LMC GC系统的运动学。除两个GC（NGC 2159和NGC 2210）外，高速度表明它们不是LMC系统的长期成员，数据与像恒星磁盘这样旋转的扁平配置一致。一维速度分散剂的速度为30 km/s，类似于LMC磁盘中的旧恒星种群。与银河系磁盘簇的情况类似，速度各向异性使得分散在方位角方向最小。但是，由于距离不确定性，不能排除替代各向异性。数据与单个多维高斯速度分布一致。鉴于LMC磁盘的非碰撞性质，这表明大多数（如果不是全部）LMC GC是由恒星磁盘中的单个地层机制形成的，尽管年龄和金属性差异显着。与银河系相比，LMC中任何积聚的Halo GC种群都不存在或小得多。
We have determined bulk proper motions (PMs) for 31 LMC GCs from Gaia eDR3 and Hubble Space Telescope data using multiple independent analysis techniques. Combined with literature values for distances, line-of-sight velocities and existing bulk PMs, we extract full 6D phase-space information for 32 clusters, allowing us to examine the kinematics of the LMC GC system in detail. Except for two GCs (NGC 2159 and NGC 2210) for which high velocities suggest they are not long-term members of the LMC system, the data are consistent with a flattened configuration that rotates like the stellar disk. The one-dimensional velocity dispersions are of order 30 km/s, similar to that of old stellar populations in the LMC disk. Similar to the case for Milky Way disk clusters, the velocity anisotropy is such that the dispersion is smallest in the azimuthal direction; however, alternative anisotropies cannot be ruled out due to distance uncertainties. The data are consistent with a single multi-dimensional Gaussian velocity distribution. Given the non-collisional nature of the LMC disk, this suggests that most, if not all, of the LMC GCs are formed by a single formation mechanism in the stellar disk, despite a significant spread in age and metallicity. Any accreted halo GC population is absent or far smaller in the LMC compared to the Milky Way.
