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arXiv 2409.07518astro-ph.GA
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PIPER巡天 II. 英仙座星系团中低表面亮度星系的球状星团系统

The PIPER Survey. II. The Globular Cluster Systems of Low Surface Brightness Galaxies in the Perseus Cluster

Steven R. Janssens, Duncan A. Forbes, Aaron J. Romanowsky, Jonah Gannon, Joel Pfeffer, Warrick J. Couch, Jean P. Brodie, William E. Harris, Patrick R. Durrell, Kenji Bekki

AI总结:

本研究利用哈勃望远镜观测英仙座星系团的50个低表面亮度星系,测量其结构与球状星团系统特征,发现富球状星团系统的尺寸与颜色规律,为超弥散星系的形成机制提供观测依据。

摘要:

我们展示了哈勃空间望远镜ACS/WFC和WFC3/UVIS对英仙座星系团中50个低表面亮度(LSB)星系样本的成像观测,这些星系最初在地面成像中被识别,该星系团质量约为10¹⁵ M☉。我们测量了这些星系的结构性质,并估算了它们所承载的球状星团(GCs)的总数。样本中约一半的星系符合超弥散星系(UDG)的严格定义,其余为类UDG星系,要么结构稍致密,要么亮度略高。少数星系拥有包含数十个GC的系统,可与后发星系团中已知的部分富GC UDG系统相媲美。我们发现,富GC系统的大小(以半数半径计)平均延伸至其宿主星系半光半径的约1.2倍。在不确定性范围内,GC系统的平均颜色与其宿主星系恒星的平均颜色一致。这表明GCs和星系场星可能在同一时期由同一富集气体形成。这也可能表明,瓦解的GCs对宿主星系的恒星成分有显著贡献,这与UDG的“失败星系”形成理论预期相符。

英文摘要:

We present Hubble Space Telescope ACS/WFC and WFC3/UVIS imaging for a sample of 50 low surface brightness (LSB) galaxies in the $\sim$10$^{15}$ M$_{\odot}$ Perseus cluster, which were originally identified in ground-based imaging. We measure the structural properties of these galaxies and estimate the total number of globular clusters (GCs) they host. Around half of our sample galaxies meet the strict definition of an ultra-diffuse galaxy (UDG), while the others are UDG-like but are either somewhat more compact or slightly brighter. A small number of galaxies reveal systems with many tens of GCs, rivalling some of the richest GC systems known around UDGs in the Coma cluster. We find the sizes of rich GC systems, in terms of their half-number radii, extending to $\sim$1.2 times the half-light radii of their host galaxy on average. The mean colours of the GC systems are the same, within the uncertainties, as those of their host galaxy stars. This suggests that GCs and galaxy field stars may have formed at the same epoch from the same enriched gas. It may also indicate a significant contribution from disrupted GCs to the stellar component of the host galaxy as might be expected in the 'failed galaxy' formation scenario for UDGs.

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