论文标题

MOCCA调查数据库:额外的银河球状簇。 I.方法和第一个结果

MOCCA Survey Database: Extra Galactic Globular Clusters. I. Method and first results

论文作者

Leveque, Agostino, Giersz, Mirosław, Paolillo, Maurizio

论文摘要

在过去的几十年中,对额外银河系簇(EGGC)的详尽调查变得可行。直到最近,通过GAIA DR2光谱和适当的运动才能获得球状簇(GC)的运动学信息。另一方面,GC的仿真可以提供有关系统动态演变的详细信息。我们介绍了针对不同动力学进化阶段的EGGC特性的初步研究。我们将这项研究应用于模拟的12个Gyr Gyl GC,作为MOCCA调查数据库的一部分。模仿观察限制,我们仅考虑数据库中模型的子样本,表明可以表示观察到的银河系GC。为了区分EGGC的不同动态状态,至少需要三个结构参数。最好的区别是通过考虑中心参数,即观察性核心半径,中央表面亮度,中央和半质量速度散布之间的比率,或类似地考虑中心颜色,中心V幅度以及中央V幅度以及中央半径速度之间的比率和半质量速度的比率,尽管这些特性与当前技术相比可能是高度的。考虑到半光半径处的平均特性,当前组中可能可以访问类似但较少的结果。此外,我们提到,由于内部动力学模型,由于内部动力学模型而引起的颜色在EGGC中传播,由于金属性的扩散,可能同样重要。

Over the last few decades, exhaustive surveys of extra Galactic globular clusters (EGGCs) have become feasible. Only recently, kinematical information of globular clusters (GCs) were available through Gaia DR2 spectroscopy and also proper motions. On the other hand, simulations of GCs can provide detailed information about the dynamical evolution of the system. We present a preliminary study of EGGCs' properties for different dynamical evolutionary stages. We apply this study to 12 Gyr-old GCs simulated as part of the MOCCA Survey Database. Mimicking observational limits, we consider only a subssample of the models in the database, showing that it is possible to represent observed Galactic GCs. In order to distinguish between different dynamical states of EGGCs, at least three structural parameters are necessary. The best distinction is achieved by considering the central parameters, those being observational core radius, central surface brightness, ratio between central and half-mass velocity dispersion, or similarly considering the central color, the central V magnitude and the ratio between central and half-mass radius velocity dispersion, although such properties could be prohibitive with current technologies. A similar but less solid result is obtained considering the average properties at the half-light radius, perhaps accessible presently in the Local Group. Additionally, we mention that the color spread in EGGCs due to internal dynamical models, at fixed metallcity, could be just as important due to the spread in metallicity.

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