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银河 chronology 从 Gaia 颜色-光度图拟合 (ChronoGal) -- III. 银河系附近太阳附近 Gaia-Sausage-Enceladus 星的年龄和金属丰度分布

Chronology of our Galaxy from Gaia colour-magnitude diagram fitting (ChronoGal) -- III. Age and metallicity distribution of Gaia-Sausage-Enceladus stars near the Sun

Universidad de Granada（格拉纳达大学）；Instituto Carlos I de Física Teórica y Computacional, Facultad de Ciencias（理论计算物理卡洛斯一世研究所，理学院）；Instituto de Astrofísica de Canarias（加那利群岛天体物理学研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉古纳大学天体物理学系）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（博洛尼亚空间天体物理学与科学国家天文台）；Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna（博洛尼亚大学物理与天文学系）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；Institute for Computational Cosmology, Department of Physics, Durham University（达勒姆大学物理学院计算宇宙学研究所）
Yllari K. González-Koda, Tomás Ruiz-Lara, Carme Gallart, Edoardo Ceccarelli, Emma Dodd, Emma Fernández-Alvar, Santi Cassisi, Francisco Surot, Fernando Aguado-Ag… 展开作者

Yllari K. González-Koda, Tomás Ruiz-Lara, Carme Gallart, Edoardo Ceccarelli, Emma Dodd, Emma Fernández-Alvar, Santi Cassisi, Francisco Surot, Fernando Aguado-Agelet, Davide Massari, Matteo Monelli, Thomas M. Callingham, Amina Helmi, Guillem Aznar-Menargues, David Mirabal, Alicia Rivero, Anna B. Queiroz

备注：
See companion paper by Aguado-Agelet et al. 14 pages, 14 figures, 4 appendices. Submitted for publication in A&A
发表信息：
A&A 704, A259 (2025)
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AI总结：

通过 Gaia-Sausage-Enceladus 恒星的年龄和金属丰度分布，研究银河系恒星形成历史及合并事件。

摘要：

背景。Gaia-Sausage-Enceladus 被认为是贡献于银河系形成的最后一次重大合并。其残余物主导了银河系附近的吸积恒星晕。目标。我们旨在通过其恒星群体的年龄和金属丰度来表征 Gaia-Sausage-Enceladus 的恒星形成历史。方法。从 Gaia DR3 数据中，我们动态定义了三个 Gaia-Sausage-Enceladus 样本，具有不同的标准和可能的其他子结构污染程度。然后，我们使用 CMDfit.Gaia 包推导出恒星年龄和金属丰度分布。结果。我们识别出三大部分恒星群体和一个更小的群体，遵循几乎线性的年龄-[M/H] 关系。三个最古老的群体对应于持续了至少 3-4 Gyr 的恒星形成，约 10 Gyr 前结束，其金属丰度从 -1.7 到 -0.8。我们将这些群体分为两个主要时期：GSE 的孤立演化和合并事件。这种分离从 GSE 球状星团的年龄-金属丰度关系（Aguado-Agelet 等，subm.）中获得了独立支持。第四个群体更年轻且更金属丰富，约 8.5 Gyr，[M/H]≈-0.4；其与 GSE 的联系不明确。

英文摘要：

Context. Gaia-Sausage-Enceladus is considered the last major merger that contributed to the formation of the Milky Way. Its remnants dominate the nearby accreted stellar halo of the Milky Way. Aim. We aim to characterise the star formation history of Gaia-Sausage-Enceladus through the age and metallicity of its stellar populations. Methods. From Gaia DR3 data, we dynamically define three Gaia-Sausage-Enceladus samples with different criteria and possible degrees of contamination from other substructures in the halo. Then, we derive the stellar age and metallicity distributions using the CMDfit.Gaia package. Results. We identify three main populations of stars and a fourth smaller one following an almost linear age-[M/H] relation. The three oldest populations correspond to the bulk of the star formation that lasted for, at least, $\sim$3-4 Gyr and ended about 10 Gyr ago, its metallicities ranging from $-$1.7 to $-$0.8. We categorise these populations into two main epochs: the evolution of GSE in isolation and the merger event. This separation finds independent support from the age-metallicty relation of GSE globular clusters (Aguado-Agelet et al., subm.). The fourth population is younger and more metal-rich, at $\sim$8.5 Gyr and [M/H]$\sim-0.4$; its link to GSE is unclear.

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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