论文标题
绝对V波段的大小和银河球状簇的质量比率
Absolute V-band magnitudes and mass-to-light ratios of Galactic globular clusters
论文作者
论文摘要
我们已经使用HST和地面的光度法来确定150多个银河球状簇的总$ V $带量和质量比率。我们通过使用颜色障碍信息，GAIA DR2适当的运动和径向速度来概括其各个成员恒星的大小来做到这一点，以区分簇星和背景恒星。我们的新幅度证实了v <8的明亮簇的文献估计，但可以偏离淡淡的簇的文献值多达两个幅度。它们导致绝对质量与光的比率局限于狭窄范围1.4 <m/l_v <2.5，明显小于以前发现的范围。我们还发现集群的M/L_V值与其年龄之间的相关性与理论预测一致。球状簇的m/l_v比与恒星等速线的预测的M/L_V比也吻合，这反对球形簇内部的大量暗物质。我们最终发现，与M31中看到的相一致，外光晕球状簇的幅度分布具有朝向微弱的簇的尾部，而在银河系的内部不存在。
We have used HST and ground-based photometry to determine total $V$-band magnitudes and mass-to-light ratios of more than 150 Galactic globular clusters. We do this by summing up the magnitudes of their individual member stars, using color-magnitude information, Gaia DR2 proper motions and radial velocities to distinguish cluster stars from background stars. Our new magnitudes confirm literature estimates for bright clusters with V<8, but can deviate by up to two magnitudes from literature values for fainter clusters. They lead to absolute mass-to-light ratios that are confined to the narrow range 1.4<M/L_V<2.5, significantly smaller than what was found before. We also find a correlation between a cluster's M/L_V value and its age, in agreement with theoretical predictions. The M/L_V ratios of globular clusters are also in good agreement with those predicted by stellar isochrones, arguing against a significant amount of dark matter inside globular clusters. We finally find that, in agreement with what has been seen in M31, the magnitude distribution of outer halo globular clusters has a tail towards faint clusters that is absent in the inner parts of the Milky Way.
