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arXiv 2008.02806astro-ph.GA
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Hyper Suprime-Cam低表面亮度星系II:用哈勃空间望远镜研究超扩散星系团的球状星团系统

Hyper Suprime-Cam Low Surface Brightness Galaxies II: A Hubble Space Telescope Study of the Globular Cluster Systems of Ultra-Diffuse Galaxies in Groups

Jean J. Somalwar, Jenny E. Greene, Johnny P. Greco, Song Huang, Rachael L. Beaton, Andy D. Goulding, Lachlan Lancaster

摘要:

我们增加了样本的超弥漫星系(UDG)在较低密度的环境与特征的球状星团(GC)人口使用新的哈勃太空望远镜观测的9个UDG组环境。虽然我们的大部分UDG具有与正常矮星系一致的GC丰度,但其中两个UDG具有过量的GC种群。这两个UDG都具有GC光度函数,与高表面亮度星系和星团UDG一致。然后,我们将我们的九个对象与以前的研究相结合,以创建一个UDG目录,并分析了跨越独特多样环境的GC种群。我们使用这个目录来研究低恒星质量星系GC种群的更广泛的趋势。GC丰度最高的是UDG集群,但是否UDG集群实际上是更极端的需要研究更多的UDG组。我们发现GC丰度和恒星质量之间可能存在正相关关系,并且在固定恒星质量下GC丰度和星系大小之间可能存在正相关关系。然而,在我们有限的恒星质量范围内,我们没有看到显著的恒星质量与星系大小的关系。我们认为GC丰度和星系大小之间的相关性可能的起源,包括这两个星系的属性都依赖于星系暗物质晕的可能性,或者它们是通过重子过程,如内部反馈。

英文摘要:

We increase the sample of ultra diffuse galaxies (UDGs) in lower density environments with characterized globular cluster (GC) populations using new Hubble Space Telescope observations of nine UDGs in group environments. While the bulk of our UDGs have GC abundances consistent with normal dwarf galaxies, two of these UDGs have excess GC populations. These two UDGs both have GC luminosity functions consistent with higher surface brightness galaxies and cluster UDGs. We then combine our nine objects with previous studies to create a catalog of UDGs with analyzed GC populations that spans a uniquely diverse range of environments. We use this catalog to examine broader trends in the GC populations of low stellar mass galaxies. The highest GC abundances are found in cluster UDGs, but whether cluster UDGs are actually more extreme requires study of many more UDGs in groups. We find a possible positive correlation between GC abundance and stellar mass, and between GC abundance and galaxy size at fixed stellar mass. However, we see no significant stellar-mass galaxy-size relation, over our limited stellar mass range. We consider possible origins of the correlation between GC abundance and galaxy size, including the possibility that these two galaxy properties are both dependent on the galaxy dark matter halo, or that they are related through baryonic processes like internal feedback.

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