AI 中文总结
本研究结合GalWCat19星表与SDSS属性，测得后发座星系团回溅半径为$2.94\rm\thinspace h^{-1}\rm\thinspace Mpc$，通过三维分类发现回溅边界是演化过渡带，揭示星系演化是多维度连续路径。
AI 中文摘要
我们结合GalWCat19光谱星系团星表与基于SDSS的增值星系属性，研究后发座星系团完整动力学结构范围内的星系演化。我们测得回溅半径为$R_{sp}=2.94\rm\thinspace\textit{h}^{-1}\rm\thinspace Mpc$。我们以特定恒星形成率（sSFR）、红序列色偏移量（$\rm\textit{\text{Δ}(g-r)}_{RS}$）、核球-总质量比（$B/T$）为独立诊断指标，发现存在连贯的环境转变：从星系团核心的宁静、红色、核球主导型星系，到更大半径处愈发恒星形成活跃、蓝色、盘主导型的星系群。我们进一步在$(\rm\textit{log}\rm\thinspace sSFR, \rm\textit{\text{Δ}(g-r)}_{RS}, \rm\textit{B/T})$空间引入三维框架，并开发基于峰值的分类方案，该方案超越了传统一维星系分类。此框架识别出两个主导星系群：红色、宁静、核球主导型星系，占联合分析样本的51%；蓝色、恒星形成活跃、盘主导型星系，占29%；剩余约20%的星系处于连接这两个主要星系群的过渡或混合状态。这些星系群的相对占比在回溅半径附近发生剧烈变化：红色、宁静、核球主导型星系占比快速下降，蓝色、恒星形成活跃、盘主导型星系占比逐渐占据主导。这些结果表明，回溅边界不仅是动力学边界，还是关键的演化过渡带。总体而言，我们的发现提示后发座星系团内的星系演化并非纯粹的二元转变，而是沿连续的多维度路径进行，其中恒星形成淬灭、颜色演化、形态转变在不同时标上发生，同时与星系团动力学结构紧密关联。
英文摘要
We investigate galaxy evolution across the full dynamical structure of the Coma cluster using the GalWCat19 spectroscopic cluster catalog combined with SDSS-based value-added galaxy properties. We measure a splashback radius of $R_{sp} = 2.94 \pm 0.16~h^{-1}\, Mpc$. Using specific star formation rate (sSFR), color offset from the red sequence ($Δ(g-r)_{RS}$), and bulge-to-total ratio ($B/T$) as independent diagnostics, we find a coherent environmental transition from quiescent, red, bulge-dominated galaxies in the cluster core to increasingly star-forming, blue, disk-dominated populations at larger radii. We further introduce a three-dimensional framework in the joint $(\log sSFR, Δ(g-r)_{RS}, B/T)$ space and develop a peak-based classification scheme that extends beyond traditional one-dimensional galaxy classifications. This framework identifies two dominant populations: red, quiescent, bulge-dominated galaxies, which account for $51\%$ of the joint-analysis sample, and blue, star-forming, disk-dominated galaxies, which account for $29\%$. The remaining $\sim20\%$ of galaxies occupy transitional or mixed states that connect these two principal populations. The relative fractions of these populations change strongly near the splashback radius, where the red, quiescent, bulge-dominated population declines rapidly and the blue, star-forming, disk-dominated population becomes increasingly dominant. These results show that the splashback boundary is not only a dynamical boundary, but also a critical evolutionary transition zone. Overall, our findings suggest that galaxy evolution in Coma is not a purely binary transformation, but instead proceeds through continuous multidimensional pathways in which star formation quenching, color evolution, and morphological transformation occur on different timescales while remaining closely linked to the cluster dynamical structure.
CommentsAccepted for publication in the ApJ
