凸起主导星系的组装：基于混合分类流水线通过形态、运动学与环境追踪的两种演化通道
The assembly of bulge-dominated galaxies: two evolutionary channels traced through morphology, kinematics, and environment with a hybrid classification pipeline
浏览论文内容
中文总结 AI 辅助
本研究通过形态、运动学与环境分析，揭示凸起主导星系双峰性源于两种组装通道：G1（高sSFR、类盘）与G2（低sSFR、弥散主导），且高密度环境加速淬灭放大差异。
中文摘要 AI 辅助
我们结合非参数形态学度量、结构标度关系、恒星运动学以及宽红移范围（$0.2 < z < 2.4$）内的环境趋势，研究了Sampaio等人（2025）最初识别的凸起主导星系双峰性的物理起源。利用应用于CANDELS成像的基于MEGG的混合分类流水线，我们检验了两类凸起主导星系家族的形态学度量分布：G1，具有高比恒星形成率（sSFR）分布，类似于盘星系；以及G2，具有较低的sSFR。我们发现G1星系在形态学度量上占据盘星系与G2球状星系之间的中间位置，且这一行为持续到$z = 1.4$。分别对每个家族拟合Kormendy关系，我们发现所有红移下零点存在持续偏移：在固定有效半径下，G2星系在平均有效表面亮度上系统性更亮，可能表明更高的中心恒星密度。该偏移在观测星等和静止框架星等中均存在，我们认为这反映了组装历史的真实差异。与MUSE观测的交叉匹配显示，G1星系比G2星系具有更高的投影角动量，其中G1星系与盘星系群体重叠，而G2星系更受弥散主导。形态学比例的红移演化表明，在高恒星质量下，G2比例增长，而盘星系呈现相反趋势。同时，G1保持稳定、较低质量的群体，与盘状凸起的增长一致。最后，在星系团内，G1星系优先位于更大的团中心半径处，表明高密度环境通过加速淬灭放大了双峰性。
英文摘要
We investigate the physical origin of the bimodality in bulge-dominated galaxies, originally identified by Sampaio et al. (2025), by combining non-parametric morphological metrics, structural scaling relations, stellar kinematics, and environmental trends across a wide redshift range ($0.2 < z < 2.4$). Using the MEGG-based hybrid classification pipeline applied to CANDELS imaging, we examine the distributions of morphological metrics for two families of bulge-dominated galaxies: G1, with high specific star formation rate (sSFR) distributions, similar to discs, and G2 with lower sSFR. We find that G1 galaxies occupy an intermediate position between discs and G2 spheroids in morphological metrics, and this behaviour persists up to $z = 1.4$. Fitting the Kormendy relation separately for each family, we find a persistent offset in the zero-point across all redshifts: G2 galaxies are systematically brighter in mean effective surface brightness at fixed effective radius, likely indicating higher central stellar densities. This offset is present in both observed and rest-frame magnitudes, and we argue that it reflects a genuine difference in assembly history. A cross-match with MUSE observations reveals that G1 galaxies have higher projected angular momentum than G2 galaxies, with G1 galaxies overlapping with the disc population, while G2 galaxies are more dispersion-dominated. The redshift evolution of morphological fractions shows that, at high stellar masses, the G2 fraction grows, while discs follow the opposite trend. In parallel, G1 remains a stable, lower-mass population consistent with secular bulge growth. Finally, within galaxy clusters, G1 galaxies are preferentially found at larger cluster-centric radii, suggesting that high-density environments amplify the bimodality by accelerating quenching.
发表机构
- Universidade Cidade de São Paulo（圣保罗城市大学）
- Universidade de São Paulo, IAG（圣保罗大学天体物理研究所）
- California Institute of Technology（加州理工学院）
- Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）
- Universidad Técnica Federico Santa María（费德里科·Santa玛利亚技术大学）
机构由 AI 辅助整理，请以论文原文为准。
