THE FLATTENING OF GLOBULAR CLUSTERS
THE FLATTENING OF GLOBULAR CLUSTERS
复制标题
球状星团的扁平化
DOI：
10.1088/0004-6256/135/5/1731
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Sidney van den Bergh
中科院分区：
文献类型：
--
作者：
Sidney van den Bergh
在距离我们最近的三个明亮星系中，即银河系、仙女座星系和NGC 5128，最亮的球状星团比最暗的球状星团要圆。另一方面（与以前的一些结果相反），个别大麦哲伦星系团的扁平化被发现是独立于它们的光度。这暗示了星系团的光度和扁平度之间的关系可能取决于宿主星系的光度。发现银河系老晕、年轻晕和银河系核球/盘团的内禀扁平分布之间没有显著差异。如果潮汐力（在小银心距离处最大）从球状星团中去除角动量，这种依赖性可能是可以预期的。诺里斯的初步结论是，蓝色水平分支的集群比红色水平分支（HB）集群更平坦，但现在可用的更大的数据库并没有证实这一结论。换句话说，没有证据表明银河系球状星团的扁平化和水平分支形态之间令人困惑的相关性。
In the three nearest luminous galaxies, the Milky Way System, the Andromeda Galaxy, and NGC 5128, the brightest globular clusters are rounder than the faintest ones. On the other hand (contrary to some previous results) the flattening of individual Large Magellanic Cloud clusters is found to be independent of their luminosities. This suggests the possibility that the relationship between the flattening and luminosity of clusters might depend on host galaxy luminosity. No significant differences are found between the intrinsic flattening distributions of Galactic old halo, Galactic young halo, and Galactic bulge/disk clusters. Such a dependence might perhaps have been expected if tidal forces (which are largest at small Galactocentric distances) removed angular momentum from globular clusters. The preliminary conclusion by Norris that clusters with blue horizontal branches are more flattened than red horizontal-branch (HB) clusters is not confirmed by the larger database that is now available. In other words there is no evidence for the puzzling claimed correlation between the flattening and the horizontal branch morphology of Galactic globular clusters.