基于多层模型的GAMA巡天本地宇宙星系数据表征
Multi-layered model-based characterisation of the local-Universe galaxy data from the GAMA survey
AI总结：
利用t混合因子分析器和模型估计重叠合胞聚类，对GAMA巡天中的5306个星系进行概率表征，揭示了红蓝双峰中与淬灭路径、形态和环境相关的子结构。
摘要：
理解星系种群的形成和演化需要稳健的分类和表征技术，这些技术需同时考虑星系内部属性和环境。我们分析了星系与质量组装（GAMA）巡天中的5306个星系，其描述参数包括恒星质量、比恒星形成率、u-r颜色、半光半径、Sérsic指数以及由最优密度给出的组合环境度量。与基于距离的无监督聚类方法不同，我们的框架提供了星系种群的概率表征，适应重尾特征分布，并通过潜在因子捕捉观测量之间的依赖关系。我们使用具有组特定潜在结构的t混合因子分析器（M$t$FAD）对样本进行建模，然后应用模型估计重叠合胞聚类（MOBSynC）合并弱分离的组，恢复更高层次的种群结构。第一阶段识别出八个简单簇。第三和第四组位于红色、低恒星形成序列上，分别对应环境淬灭和质量淬灭系统；第六组追踪恒星形成序列的大质量端；第七组似乎代表一个更异质的种群，可能包含过渡天体。其余组位于低到中等质量的蓝色序列，包括致密和更延展的恒星形成星系。第二阶段的MOBSynC将简单簇合并为两个复合组：由第三和第四组形成的红色序列，以及其余组合并形成的宽蓝色序列。我们的结果表明，本地星系常见的红蓝双峰包含与淬灭路径、形态和环境相关的额外物理上有意义的子结构。
英文摘要：
Understanding the formation and evolution of galaxy populations requires robust classification and characterisation techniques that jointly account for internal galaxy properties and environment. We analyse $5,306$ galaxies from the Galaxy And Mass Assembly (GAMA) survey, described by stellar mass, specific star formation rate, $u-r$ colour, half-light radius, Sérsic index, and a combined environmental measure given by the optimal density. Unlike distance-based unsupervised clustering methods, our framework provides a probabilistic characterisation of galaxy populations, accommodates heavy-tailed feature distributions, and captures dependence among observables through latent factors. We model the sample using a $t$-mixture of factor analysers with group-specific latent structures (M$t$FAD), and then apply model-estimated overlap-based syncytial clustering (MOBSynC) to merge weakly separated groups and recover higher-level population structure. The first stage identifies eight simple clusters. The third and the fourth groups lie on the red, low-star-forming sequence and correspond to environmentally quenched and mass-quenched systems, respectively, while the sixth group traces the massive end of the star-forming sequence, and the seventh group appears to represent a more heterogeneous population that may include transition objects. The remaining groups populate the low- to intermediate-mass blue sequence, including both compact and more extended star-forming galaxies. The second MOBSynC stage merges the simple clusters into two compound groups: a red sequence formed by the third and the fourth groups, and the rest merging to form a broad blue sequence. Our results show that the familiar red-blue bimodality of local galaxies contains additional physically meaningful substructure linked to quenching pathway, morphology, and environment.
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。
