Evolution of Globular Cluster Systems in Elliptical Galaxies
Evolution of Globular Cluster Systems in Elliptical Galaxies
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椭圆星系中球状星团系统的演化
DOI：
10.1046/j.1365-8711.2000.03869.x
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
E. Vesperini
中科院分区：
文献类型：
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作者：
E. Vesperini
研究了椭圆星系中球状星团系统的演化，探讨了其主要性质与宿主星系质量和大小的关系。
我们把我们的注意力集中在GCS质量函数（GCMF）的演化，幸存的集群的分数和集群的最终初始总质量的比率;这些GCS属性的依赖关系的主机星系的结构以及它们的变化与银河系的距离内个别主机星系进行了彻底的调查。我们采用对数正态初始GCMF的平均质量和色散（log Mi=5.25和σi=0.6）类似于在椭圆星系的外部区域中观察到的初始条件的记忆很可能被很好地保存。
经过大量的不同的宿主星系的调查，我们限制我们的注意力与有效质量，我和半径，Re，等于那些观察到的矮，正常和巨大的椭圆星系的样本。
我们发现，尽管幸存星系团的比例有很大的差异，但大质量星系（log Me = 10.5）的GCMF的最终平均质量log Mf彼此非常相似（log Mf = 5.16，MV=-7.3，假设MLV=2），具有较小的星系-星系色散;低质量致密星系倾向于具有较小的log Mf值和较大的星系-星系色散。这些发现与最近的观察分析结果一致。
幸存星系团的比例NfNi随着宿主星系的质量而增加，范围从最大质量星系的NfNi <$0.9到矮星系的NfNi <$0.1。我们发现，GCMF的初始和最终的平均质量和色散之间的一个小的差异和缺乏一个显着的径向依赖性的日志MF内个别星系并不一定意味着演化过程中的初始人口的集群的演变是不重要的。对于巨大的星系，大多数分裂发生在有效半径内，而对于低质量星系，星系团的显着分裂也发生在更大的银河系中心距离。
得到的结果对GCMF的初始平均质量的依赖性也进行了研究，结果表明，在4.7 μ log Mi ~ 5.5的区间之外，log Mf的扩展和数值与观测结果不一致。
We study the evolution of globular cluster systems (GCS) in elliptical galaxies and explore the dependence of their main properties on the mass and the size of the host galaxy.
We focus our attention on the evolution of the GCS mass function (GCMF), on the fraction of surviving clusters and on the ratio of the final to initial total mass in clusters; the dependence of these GCS properties on the structure of the host galaxy as well as their variation with the galactocentric distance inside individual host galaxies is thoroughly investigated. We adopt a log-normal initial GCMF with mean mass and dispersion (log Mi=5.25 and σi=0.6) similar to those observed in the external regions of elliptical galaxies where memory of initial conditions is likely to be well preserved.
After a survey over a large number of different host galaxies we restrict our attention to a sample of galaxies with effective masses, Me, and radii, Re, equal to those observed for dwarf, normal and giant ellipticals.
We show that, in spite of large differences in the fraction of surviving clusters, the final mean masses, log Mf, of the GCMF in massive galaxies (log Me≳10.5) are very similar to each other (log Mf≃5.16, MV=−7.3, assuming MLV=2) with a small galaxy-to-galaxy dispersion; low-mass compact galaxies tend to have smaller values of log Mf and a larger galaxy-to-galaxy dispersion. These findings are in agreement with those of recent observational analyses.
The fraction of surviving clusters, NfNi, increases with the mass of the host galaxy, ranging from NfNi∼0.9 for the most massive galaxies to NfNi∼0.1 for dwarf galaxies. We show that a small difference between the initial and the final mean mass and dispersion of the GCMF and the lack of a significant radial dependence of log Mf inside individual galaxies do not necessarily imply that evolutionary processes have been unimportant in the evolution of the initial population of clusters. For giant galaxies most disruption occurs within the effective radius, while for low-mass galaxies a significant disruption of clusters takes place also at larger galactocentric distances.
The dependence of the results obtained on the initial mean mass of the GCMF is also investigated, and it is shown that outside the interval 4.7≲log Mi≲5.5 both the spread and the numerical values of log Mf are not consistent with those observed.