ACS天炉座星团巡天。VIII。室女座和天炉座早型星系团中球状星团的光度函数及其作为距离指示的应用
The ACS Fornax Cluster Survey. VIII. The Luminosity Function of Globular Clusters in Virgo and Fornax Early-Type Galaxies and its Use as a Distance Indicator
摘要:
我们利用室女座和天炉座星系团中132个早型星系的一组高度均匀的数据来研究球状星团光度函数(GCLF)的性质。每个星系的球状星团系统进行了研究,使用极大似然的方法来模拟的内在GCLF后,占污染和完整性的影响。这里给出的结果更新了我们的室女座测量结果,并证实了我们以前的结果,即GCLF的色散与母星系的绝对星等之间存在紧密的相关性。关于使用的GCLF作为标准蜡烛,我们已经发现,室女座和天炉座集群之间的相对距离模量是系统地低于其他距离估算得出的,特别是它是0.22mag低于从表面亮度波动测量相同的数据进行的值。从数值模拟,旨在再现观察到的分散的值的周转在每个星系团,我们估计一个内在的分散在这个参数上的室女座和天炉座分别为0.21等和0.15等。总而言之,我们的研究表明,GCLF的性质随星系质量的变化而系统地变化,没有证据表明巨和矮早型星系之间存在二分法。这些属性可能会受到宇宙学模拟所建议的集群环境的影响。
英文摘要:
We use a highly homogeneous set of data from 132 early-type galaxies in the Virgo and Fornax clusters in order to study the properties of the globular cluster luminosity function (GCLF). The globular cluster system of each galaxy was studied using a maximum likelihood approach to model the intrinsic GCLF after accounting for contamination and completeness effects. The results presented here update our Virgo measurements and confirm our previous results showing a tight correlation between the dispersion of the GCLF and the absolute magnitude of the parent galaxy. Regarding the use of the GCLF as a standard candle, we have found that the relative distance modulus between the Virgo and Fornax clusters is systematically lower than the one derived by other distance estimators, and in particular it is 0.22mag lower than the value derived from surface brightness fluctuation measurements performed on the same data. From numerical simulations aimed at reproducing the observed dispersion of the value of the turnover magnitude in each galaxy cluster we estimate an intrinsic dispersion on this parameter of 0.21mag and 0.15mag for Virgo and Fornax respectively. All in all, our study shows that the GCLF properties vary systematically with galaxy mass showing no evidence for a dichotomy between giant and dwarf early-type galaxies. These properties may be influenced by the cluster environment as suggested by cosmological simulations.
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