论文标题
球状簇RUP 106和IC 4499的动力状态
The dynamical state of the globular clusters Rup 106 and IC 4499
论文作者
论文摘要
球状簇的动态演化理论上是由N体系统的一系列典型事件描述的。尽管如此，能够鉴定能够凭经验描述球状簇典型密度的恒星系统动力学演化的阶段的鉴定，这是一个挑战。在本文中，我们研究了球状簇RUP 106和IC 4499的动力时代。为了实现这一目标，我们通过A+参数研究了蓝色Straggler恒星的径向分布以及主序列质量函数的斜率。两个示踪剂都表明，RUP 106和IC 4499是动态的年轻簇，动态摩擦刚刚开始将巨大的恒星隔离到簇的中心。实际上，我们观察到，蓝色straggler恒星在两个集群中比参考人群更集中。在同一条线上，我们发现在这两种情况下，质量函数的斜率都随着以群集为中心的距离显着降低。该结果为使用蓝色散乱者的径向分布作为强大的观察方便指标提供了额外的支持。
The dynamical evolution of globular clusters is theoretically described by a series of well known events typical of N-body systems. Still, the identification of observational signatures able to empirically describe the stage of dynamical evolution of a stellar system of the density typical of a globular cluster, represents a challenge. In this paper we study the dynamical age of the globular clusters Rup 106 and IC 4499. To this aim, we study the radial distribution of the Blue Straggler Stars via the A+ parameter and of the slope of the Main Sequence Mass Function. Both tracers show that Rup 106 and IC 4499 are dynamically young clusters where dynamical friction has just started to segregate massive stars towards the clusters' centre. In fact, we observe that the Blue Straggler stars are more centrally concentrated in both clusters than the reference population. On the same line, we find that in both cases the slope of the mass function significantly decreases as a function of the cluster-centric distances. This result provides additional support for the use of the the radial distribution of the blue stragglers as a powerful observationally convenient indicator of the cluster dynamical age.
