On the structure of globular cluster systems in elliptical galaxies
On the structure of globular cluster systems in elliptical galaxies
复制标题
椭圆星系球状星团系统的结构
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Kenji BekkiDuncan A. Forbes
中科院分区：
文献类型：
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作者：
Kenji BekkiDuncan A. Forbes
椭圆形星系中球状星系团(GCS)的径向密度分布随其所在星系的总光度而变化。为了阐明GCSs结构不一致性的起源，我们数值研究了由一系列主要的无耗散星系合并而成的椭圆星系中GCSs的结构性质。我们发现，随着星系经历更多的重大合并事件，椭圆星系中GCS的径向密度分布逐渐变得平坦。椭圆体中GCS的密度分布可以很好地描述为斜率为-2.0到-1.0的幂函数(αge)。它们比其宿主星系的恒星密度剖面的斜率(αS)平坦，并与之成线性比例。我们还发现，在合并次数较多的椭圆体中，密度分布的GCS核心半径(Rc)较大。通过在模拟结果中应用一个合理的亮度与星系大小之间的标度关系，我们得到了αGe-0.36mv-9.2，rc-1.85mV，αGC0.93α，其中MV是一个星系的总V带绝对星等。我们将这些预测与观测结果进行比较，并讨论它们的物理意义。我们认为，椭圆形星云的结构不一致性可以用主要的无耗散星系合并所导致的椭圆星增长来解释。
It has long been known that the radial density profiles of globular cluster systems (GCSs) in elliptical galaxies vary with the total luminosities of their host galaxies. In order to elucidate the origin of this structural non-homology in GCSs, we numerically investigate the structural properties of GCSs in elliptical galaxies formed from a sequence of major dissipationless galaxy merging. We find that the radial density profiles of GCSs in elliptical galaxies become progressively flatter as the galaxies experience more major merger events. The density profiles of GCSs in ellipticals are well described as power-laws with slopes (α ge ) ranging from -2.0 to -1.0. They are flatter than, and linearly proportional to, the slopes (α s ) of the stellar density profiles of their host galaxies. We also find that the GCS core radii (r c ) of the density profiles are larger in ellipticals that experienced more mergers. By applying a reasonable scaling relation between luminosities and sizes of galaxies to the simulation results, we show that α ge -0.36M v - 9.2, r c -1.85M V , and α gc 0.93α, where M V is the total V-band absolute magnitude of a galaxy. We compare these predictions with observations and discuss their physical meaning. We suggest that the origin of structural non-homology of GCSs in ellipticals can be understood in terms of the growth of ellipticals via major dissipationless galaxy merging.