重新加载的ESO-VLT MIKiS调查：NGC 1904的速度弥散剖面和旋转曲线
The ESO-VLT MIKiS survey reloaded: velocity dispersion profile and rotation curve of NGC 1904
摘要：
本文研究了M79（NGC 1904）的内部运动学性质。我们的研究是基于从银河系球状星团的ESO-VLT多仪器运动学巡天（MIKiS）获得的径向速度测量值，这些球状星团分布在$\sim 0.3^{\prime\prime}$和$770^{\prime\prime}$（$\sim14$三维半质量半径）之间，从中心开始，超过1700颗恒星。我们的分析揭示了存在有序的视线旋转与旋转轴几乎对齐沿东西方向和速度峰值$1.5$公里的$^{-1}$在$\sim 70^{\prime\prime}$从旋转轴。的速度色散曲线是很好地描述了相同的国王模型，最适合的投影密度分布，在$σ_0\sim 6$公里的$^{-1}$与恒定的中央高原。为了研究星系团在天空平面内的旋转，我们分析了盖亚EDR 3提供的自行，发现在距离星系团中心$\sim 80^{\prime\prime}$处有一个最大振幅为$\sim 2.0$ km s $^{-1}$的旋转信号。通过对130颗恒星的三维速度分布进行分析，我们确认了系统自转的存在，并发现自转轴相对于视线的倾角为$37$ °。最后，将观测到的旋转曲线与一个旋转星团的代表性N体模拟结果进行比较，结果表明NGC 1904的现今运动学性质与一个动力学古老系统的运动学性质是一致的，该系统已经失去了其初始角动量的很大一部分。
英文摘要：
We present an investigation of the internal kinematic properties of M79 (NGC 1904). Our study is based on radial velocity measurements obtained from the ESO-VLT Multi-Instrument Kinematic Survey (MIKiS) of Galactic globular clusters for more than 1700 individual stars distributed between $\sim 0.3^{\prime\prime}$ and $770^{\prime\prime}$ ($\sim14$ three-dimensional half-mass radii), from the center. Our analysis reveals the presence of ordered line-of-sight rotation with a rotation axis almost aligned along the East-West direction and a velocity peak of $1.5$ km s$^{-1}$ at $\sim 70^{\prime\prime}$ from the rotation axis. The velocity dispersion profile is well described by the same King model that best fits the projected density distribution, with a constant central plateau at $σ_0\sim 6$ km s$^{-1}$. To investigate the cluster rotation in the plane of the sky, we have analyzed the proper motions provided by the Gaia EDR3, finding a signature of rotation with a maximum amplitude of $\sim 2.0$ km s$^{-1}$ at $\sim 80^{\prime\prime}$ from the cluster center. Analyzing the three-dimensional velocity distribution, for a sub-sample of 130 stars, we confirm the presence of systemic rotation and find a rotation axis inclination angle of $37$° with respect to the line-of-sight. As a final result, the comparison of the observed rotation curves with the results of a representative N-body simulation of a rotating star cluster shows that the present-day kinematic properties of NGC 1904 are consistent with those of a dynamically old system that has lost a significant fraction of its initial angular momentum.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
