淬火锻造：EAGLE 模拟中恒星形成星系与静止星系间的形态转变
Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLE
- Institute for Computational Cosmology, Department of Physics, Durham University（达勒姆大学物理学院宇宙计算研究所）
- Centre for Extragalactic Astronomy, Department of Physics, Durham University（达勒姆大学物理学院河外天文学中心）
- Institute for Data Science, Durham University（达勒姆大学数据科学研究所）
- Center for Astronomy and Astrophysics and Department of Physics, Fudan University（复旦大学物理学院天文与天体物理中心）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究利用 EAGLE 模拟追踪星系前身，揭示形态与淬火的四种物理通道，表明形态主动促进 SMBH 增长和星系淬火，而非被动继承。
AI中文摘要：
中心星系中形态与淬火之间的联系已被充分确立，但其物理起源仍存在广泛争议。我们通过追踪 EAGLE 宇宙学模拟中 $z\gtrsim4$ 至 $z=0$ 的恒星形成和静止中心星系的主 progenitor 分支来解决这一问题。它们的盘-总比和 triaxiality 轨迹在 $z\approx 1$-$2$ 之前无法区分，此时两者随淬火开始同时发散，而大小和超大质量黑洞（SMBH）质量的差异则更早确立。我们确定了四种连接星系形态与淬火的物理上不同的通道。首先，并合导致大小增长、旋转抑制、triaxiality 增加和 SMBH 增长，累积的 SMBH 质量随后导致星系淬火。其次，在控制并合历史的情况下，星系形态在整个恒星形成阶段调节 SMBH 增长：致密、色散主导的星系其 SMBH 增长更快，并优先被淬火，从而产生恒星形成星系与静止星系之间的大小和形态差异。第三，在固定恒星质量和 SMBH 质量下，致密性进一步促进星系淬火。第四，盘不稳定性将致密的扁盘转变为长球系统，伴随显著的大小增长和旋转抑制，但恒星质量增长可忽略。这一 secular 通道贡献了 $M_{\rm star}\approx 10^{10.6}\\,\rm M_\odot$ 附近约一半的长球星系群体。在淬火之前，静止星系的前身已比同一时期的恒星形成星系具有更小的尺寸、更低的盘-总比和更巨大的 SMBH，其差异幅度与它们在 $z=0$ 时的差异相当。因此，形态在增长 SMBH 和淬火星系中扮演主动角色，而非通过前身偏差被动继承。
英文摘要：
The connection between morphology and quenching in central galaxies is well established, but its physical origin remains widely debated. We address this by tracing the main progenitor branches of $z=0$ star-forming and quiescent central galaxies in the EAGLE cosmological simulation from $z\gtrsim4$. Their disc-to-total ratio and triaxiality tracks are indistinguishable until $z\approx 1$-$2$, when both diverge concurrently with the onset of quenching, whereas the size and supermassive black hole (SMBH) mass differences are established earlier. We identify four physically distinct channels linking galaxy morphology and quenching. First, mergers cause size growth, rotation suppression, triaxiality increase, and SMBH growth, with the accumulated SMBH mass subsequently causes the quenching of galaxies. Second, with merger history controlled, galaxy morphology modulates SMBH growth throughout the star-forming phase: compact, dispersion-dominated galaxies grow their SMBHs faster and are preferentially quenched, producing the size and morphology differences between star-forming and quiescent galaxies. Third, at fixed stellar mass and SMBH mass, compactness further facilitates the quenching of galaxies. Fourth, disc instability transforms compact oblate discs into prolate systems, with substantial size growth and suppressed rotation but negligible stellar mass growth. This secular channel contributes about half of the prolate galaxy population around $M_{\rm star}\approx 10^{10.6}\,\rm M_\odot$. Prior to quenching, the progenitors of quiescent galaxies already have smaller sizes, lower disc-to-total ratios, and more massive SMBHs than star-forming galaxies at the same epoch, by amounts comparable to their differences at $z=0$. Morphology therefore plays an active role in growing the SMBH and quenching the galaxy, rather than being passively inherited through progenitor bias.
