论文标题
在潮汐场中旋转恒星簇的早期动力演变
Early dynamical evolution of rotating star clusters in a tidal field
论文作者
论文摘要
为了探索恒星簇的早期内部旋转特性如何受到宿主星系的外部潜力的影响，我们已经在早期的动力学演化和嵌入在潮汐场中的旋转星形群体的旋转星形簇的剧烈放松后，运行了一套$ n $ body的模拟。我们的研究重点是簇旋转轴相对于潮汐场的扭矩具有通用方向的模型。暴力弛豫过程，簇的角动量与外部扭矩之间的相互作用在簇内部产生了复杂的运动学结构，最显着地沿极性和方位角方向旋转轴的位置径向变化。我们还检查了集群的速度分散各向异性，并表明投影的各向异性可能受到群集内旋转轴方向的变化的影响；投影效应和复杂运动特征的组合可能会导致群集内部区域中切向各向异性的测量。我们还表征了簇的结构特性，这是它们初始旋转和病毒比率的函数，发现簇可能会发展出三轴形态和次要轴的径向变化，不一定与旋转轴对齐。最后，我们研究了这些复杂的运动学特征的长期演变。
In order to explore how the early internal rotational properties of star clusters are affected by the external potential of their host galaxies, we have run a suite of $N$-body simulations following the early dynamical evolution and violent relaxation of rotating star clusters embedded in a tidal field. Our study focuses on models for which the cluster's rotation axis has a generic orientation relative to the torque of the tidal field. The interaction between the violent relaxation process, angular momentum of the cluster, and the external torque creates a complex kinematic structure within the cluster, most prominently a radial variation in the position of the rotation axis along both the polar and azimuthal directions. We also examine the cluster's velocity dispersion anisotropy and show that the projected anisotropy may be affected by the variation of the rotation axis directions within the cluster; the combination of projection effects and the complex kinematical features may result in the measurement of tangential anisotropy in the cluster's inner regions. We also characterize the structural properties of our clusters as a function of their initial rotation and virial ratio and find that clusters may develop a triaxial morphology and a radial variation of the minor axis not necessarily aligned with the rotation axis. Finally, we examine the long-term evolution of these complex kinematic features.
