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arXiv 2509.08040astro-ph.GAastro-ph.CO
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COSMOS-Web星系群:红序列和静止星系分数的演化

COSMOS-Web galaxy groups: Evolution of red sequence and quiescent galaxy fraction

University of Bologna(博洛尼亚大学);INAF – Osservatorio di Astrofisica e Scienza dello Spazio(意大利国家天体物理研究所空间天文观测站);Zentrum für Astronomie, Universität Heidelberg(海德堡大学天体物理中心);Institut für Theoretische Physik, Universität Heidelberg(海德堡大学理论物理研究所);INFN – Sezione di Bologna(意大利国家核物理研究所博洛尼部分会);Aalto University(阿尔托大学);University of Helsinki(赫尔辛基大学);University of California, Riverside(加州大学河滨分校)
Greta Toni, Matteo Maturi, Gianluca Castignani, Lauro Moscardini, Ghassem Gozaliasl, Alexis Finoguenov, Sina Taamoli, B. Hollis Akins, C. Rafael Arango-Toro, M.… 展开作者

Greta Toni, Matteo Maturi, Gianluca Castignani, Lauro Moscardini, Ghassem Gozaliasl, Alexis Finoguenov, Sina Taamoli, B. Hollis Akins, C. Rafael Arango-Toro, M. Caitlin Casey, E. Nicole Drakos, L. Andreas Faisst, Carter Flayhart, Maximilien Franco, Fabrizio Gentile, Ali Hadi, Santosh Harish, Hossein Hatamnia, Olivier Ilbert, Shuowen Jin, S. Jeyhan Kartaltepe, Ali Ahmad Khostovan, M. Anton Koekemoer, Gavin Leroy, E. Georgios Magdis, Henry Joy McCracken, Jed McKinney, Louise Paquereau, Jason Rhodes, R. Michael Rich, E. Brant Robertson, M. Rasha Samir, Diana Scognamiglio, Samaneh Shamyati, Marko Shuntov, A. Jorge Zavala

AI总结:

该研究利用COSMOS-Web星系群数据,探讨了从z=0到z=3.7的红序列参数和静止星系分数随红移和群 richness 的演化,发现静止星系在群中逐渐积累,最丰富的群增长更快且更早,且在z≈2时首次星系定居在红序列上,还发现z=3.4处静止星系的稀疏区域,以及X射线弱群的静止星系分数较低。

摘要:

我们研究了COSMOS星系群中从z=0到z=3.7的红移和群 richness 对静止分数和红序列(RS)参数的影响。我们分析了在COSMOS(-Web)区域通过AMICO检测的深度且特征良好的星系群样本。我们的静止星系人口研究基于一种基于余弦光度的机器学习分类工具,该工具通过几种传统方法学习估计恒星是否静止,实现了高精度和召回率。从该分类开始,我们通过两种方法计算群内的静止星系分数:一种基于AMICO提供的成员概率,依赖于分析模型;另一种使用模型无关技术。然后我们通过估计光度数据的 ridgeline 位置来检测红序列,接着通过sigma clipping去除异常值。此分析使用了余弦帧和观测帧的光度数据,并通过余弦帧匹配进行匹配。我们比较了两种方法的结果,并研究了RS参数的红移和 richness 依赖性。我们发现,群中的静止星系在z=1.5-2范围内逐渐积累,最丰富的群增长更快且更早。第一个星系在z≈2时定居在红序列上,这与当前的演化场景一致。值得注意的是,我们报告了在z=3.4处静止星系的稀疏区域,可能是迄今为止最远的早期红序列。扩展我们的研究到X射线,我们发现X射线弱群的静止星系分数通常低于X射线亮群,这可能反映了它们通常位于丝状结构中。利用COSMOS2025的宽波长覆盖范围,我们追踪了红序列在约12 Gyr内的演化,发现红序列的斜率和散射没有显著趋势。

英文摘要:

We investigate the redshift and group richness dependence of the quiescent fraction and red-sequence (RS) parameters in COSMOS galaxy groups from z=0 to z=3.7. We analyzed the deep and well-characterized sample of groups detected with AMICO in the COSMOS(-Web) field. Our study of the quiescent galaxy population is based on a machine-learning classification tool based on rest-frame magnitudes. The algorithm learns from several traditional methods to estimate the probability of a galaxy being quiescent, achieving high precision and recall. Starting from this classification, we computed quiescent galaxy fractions within groups via two methods: one based on the membership probabilities provided by AMICO, which rely on an analytical model, and another using a model-independent technique. We then detected the RS by estimating the ridgeline position using photometric data, followed by sigma clipping to remove outliers. This analysis was performed using both rest-frame and observed-frame magnitudes with rest-frame matching. We compared the results from both approaches and investigated the $z$ and richness dependence of the RS parameters. We found that the quiescent galaxy population in groups builds up steadily from z=1.5-2 across all richnesses, with faster and earlier growth in the richest groups. The first galaxies settle onto the RS ridgeline by $z \sim 2$, consistent with current evolutionary scenarios. Notably, we reported a rare overdensity of quiescent galaxies at z=3.4, potentially one of the most distant early RSs observed. Extending our study to X-rays, we found that X-ray faint groups have, on average, lower quiescent fractions than X-ray bright ones, likely reflecting their typical location in filaments. Leveraging the broad wavelength coverage of COSMOS2025, we traced RS evolution over $\sim 12$ Gyr, finding no significant trends in either slope or scatter of the ridgeline.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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