论文标题
九个内部银河系的结构和内部运动学
Structure and Internal Kinematics of Nine Inner Milky Way Globular Clusters
论文作者
论文摘要
这项研究构成了更大的努力的一部分,旨在更好地表征位于银河系内部凸出和磁盘的银河球状簇(GGC)。在这里,我们专注于9个GGC的内部运动学,从$> $ 9年的时间基准中获得的空间成像获得。我们利用多种途径来评估目标GGC的动力状态,构建了投影恒星密度,适当运动分散和各向异性的径向谱。我们认为,我们的目标GGC的三分之二(6/9)处于晚期动力学状态,并且接近(或最近已经经历了)核心崩溃,至少有两条证据支持:首先,我们发现相对较陡峭的适当的运动分散曲线,符合核心凝胶GGCS的文献值。其次,我们发现我们的样品均匀地是各向同性的,尽管我们的目标簇之一(NGC 6380)是各向异性的,$> $> $σ$超出了半光线半径,但根据其在强细胞中的理论预测,其范围超出了半光线范围。我们的适当运动分散和各向异性概况公开可用。
This study constitutes part of a larger effort aimed at better characterizing the Galactic globular clusters (GGCs) located towards the inner Milky Way bulge and disk. Here, we focus on internal kinematics of nine GGCs, obtained from space-based imaging over time baselines of $>$9 years. We exploit multiple avenues to assess the dynamical state of the target GGCs, constructing radial profiles of projected stellar density, proper motion dispersion, and anisotropy. We posit that two-thirds (6/9) of our target GGCs are in an advanced dynamical state, and are close to (or have recently undergone) core collapse, supported by at least two lines of evidence: First, we find relatively steep proper motion dispersion profiles, in accord with literature values for core-collapsed GGCs. Second, we find that our sample is, in the mean, isotropic even out to their half-light radii, although one of our target clusters (NGC 6380) is tangentially anisotropic at $>$1$σ$ beyond its half-light radius, in accord with theoretical predictions for clusters evolving in strong tidal fields. Our proper motion dispersion and anisotropy profiles are made publicly available.