论文标题
由Gaia正确运动确定的开放群集半径的目录
A catalogue of open cluster radii determined from Gaia proper motions
论文作者
论文摘要
在这项工作中，我们改进了一种先前发表的方法，以可靠的方式计算开放群集的半径。该方法基于在位置空间中采样变化时恒星在适当运动空间中的行为。在这里，我们描述了该方法的新版本，并显示其性能和鲁棒性。此外，我们使用Gaia DR2的数据将其应用于大量的开放式群集，以生成具有可靠半径估计的401个簇的目录。获得的明显半径的范围从RC = 1.4+-0.1 Arcmin（对于群集FSR 1651）到RC = 25.5+-3.5 Arcmin（对于NGC〜2437）。群集线性尺寸非常接近以射线正态分布，平均特征半径为rc = 3.7 pc，其高半径尾巴可以用幂律将其拟合为n \ propto rc^（-3.11+-0.35）。此外，我们发现成员的数量，群集半径和年龄遵循关系NC \ Propto rc^（1.2+-0.1）TC^（ - 1.9+-0.4），其中年轻且更广泛的群集群，其提出的成员越多。所提出的方法对恒星的低密度或不规则空间分布不敏感，因此是一个很好的替代或互补程序，可以计算开放群集半径没有以前的恒星成员资格。
In this work we improve a previously published method to calculate in a reliable way the radius of an open cluster. The method is based on the behaviour of stars in the proper motion space as the sampling changes in the position space. Here we describe the new version of the method and show its performance and robustness. Additionally, we apply it to a large number of open clusters using data from Gaia DR2 to generate a catalogue of 401 clusters with reliable radius estimations. The range of obtained apparent radii goes from Rc=1.4+-0.1 arcmin (for the cluster FSR 1651) to Rc=25.5+-3.5 arcmin (for NGC~2437). Cluster linear sizes follow very closely a lognormal distribution with a mean characteristic radius of Rc=3.7 pc, and its high radius tail can be fitted by a power law as N \propto Rc^(-3.11+-0.35). Additionally, we find that number of members, cluster radius and age follow the relationship Nc \propto Rc^(1.2+-0.1) Tc^(-1.9+-0.4) where the younger and more extensive the cluster, the more members it presents. The proposed method is not sensitive to low density or irregular spatial distributions of stars and, therefore, is a good alternative or complementary procedure to calculate open cluster radii not having previous information on star memberships.
