标题： 球状星团NGC3201在雅可比半径以外的动力学特性 显示英文标题

标题： The dynamics of the globular cluster NGC3201 out to the Jacobi radius

摘要： 作为对使用2dF/AAOmega在AAT上进行的五个附近球状星团的化学动力学调查的一部分，我们获得了球状星团NGC3201的动力学信息。我们的新观测证实了星团中存在显著的速度梯度，这几乎可以完全由星团的高自行运动解释。在减去这种视向旋转的贡献后，我们发现了一个剩余的旋转信号，其振幅为$\sim1\ km/s$，围绕一个与我们从潮汐尾和潜在逃逸者预期不同的轴，表明这种旋转是内部的，可能是其形成过程的遗迹。在外围部分，我们发现了一个可能由潜在逃逸者引起的旋转信号。Bianchini等人报告的大半径自行弥散之前被认为是由暗物质引起的。在这里，我们显示在0.5-1个雅可比半径之间的视线弥散较低，但仍高于我们为此研究运行的NGC3201的N体模型的预测。根据模拟，我们发现潜在逃逸者无法完全解释观测到的速度弥散。我们还估算了不同数量的恒星级黑洞和来自潮汐尾的不同逃逸率的未束缚恒星对速度弥散的影响，并发现这些影响无法解释视线弥散与N体模型之间的差异。鉴于最近在远离星团的区域发现了潮汐尾恒星，暗物质晕是一个不太可能的解释。我们表明，N体模型中未包含的双星效应很重要，并可以解释弥散部分差异。我们推测剩余的差异必须是N体模型中未包含的效果的结果，例如初始星团旋转、速度各向异性和银河系次结构。 显示英文摘要

摘要： As part of a chemo-dynamical survey of five nearby globular clusters with 2dF/AAOmega on the AAT, we have obtained kinematic information for the globular cluster NGC3201. Our new observations confirm the presence of a significant velocity gradient across the cluster which can almost entirely be explained by the high proper motion of the cluster. After subtracting the contribution of this perspective rotation, we found a remaining rotation signal with an amplitude of $\sim1\ km/s$ around a different axis to what we expect from the tidal tails and the potential escapers, suggesting that this rotation is internal and can be a remnant of its formation process. At the outer part, we found a rotational signal that is likely a result from potential escapers. The proper motion dispersion at large radii reported by Bianchini et al. has previously been attributed to dark matter. Here we show that the LOS dispersion between 0.5-1 Jacobi radius is lower, yet above the predictions from an N-body model of NGC3201 that we ran for this study. Based on the simulation, we find that potential escapers cannot fully explain the observed velocity dispersion. We also estimate the effect on the velocity dispersion of different amounts of stellar-mass black holes and unbound stars from the tidal tails with varying escape rates and find that these effects cannot explain the difference between the LOS dispersion and the N-body model. Given the recent discovery of tidal tail stars at large distances from the cluster, a dark matter halo is an unlikely explanation. We show that the effect of binary stars, which is not included in the N-body model, is important and can explain part of the difference in dispersion. We speculate that the remaining difference must be the result of effects not included in the N-body model, such as initial cluster rotation, velocity anisotropy and Galactic substructure.