Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLE
Abstract
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≳4. Their disc-to-total ratio and triaxiality tracks are indistinguishable until z≈ 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 Mstar≈ 1010.6 M⊙. 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.
Related
- The quenching time and timescale distribution of z~2 quiescent galaxies from precise colour distribution analysis
- The Size-Mass Relation and Inside-Out Quenching of Massive Quiescent Galaxies at 2<z<3 with JWST PRIMER and MINERVA
- A Dusty Quenching-candidate AGN host at z=5.7: massive quiescent galaxies may quench already during the dust-obscured phase
- The Neutral Hydrogen Gas Content of Star-forming and Quiescent S0 Galaxies
- StAGE: Stellar Archaeology-driven Galaxy Evolution II. Binary Black Hole Mergers in Quiescent Galaxies and their Star-forming Progenitors
BibTeX
@misc{wang2026forged,
title = {{Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLE}},
author = {Kai Wang and Carlton Baugh and Sownak Bose and Shaun Cole and Carlos S. Frenk and Hao Fu and Cedric Lacey and Shengdong Lu and Aaron Ludlow and Peder Norberg and Yingjie Peng and Katy L. Proctor and Isabel Santos-Santos and Francesco Shankar and Tom Theuns and Enci Wang and Tao Wang and Vivienne Wild},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16187},
eprint = {2609.16187},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16187},
}
RIS
TY - UNPB
TI - Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLE
AU - Kai Wang
AU - Carlton Baugh
AU - Sownak Bose
AU - Shaun Cole
AU - Carlos S. Frenk
AU - Hao Fu
AU - Cedric Lacey
AU - Shengdong Lu
AU - Aaron Ludlow
AU - Peder Norberg
AU - Yingjie Peng
AU - Katy L. Proctor
AU - Isabel Santos-Santos
AU - Francesco Shankar
AU - Tom Theuns
AU - Enci Wang
AU - Tao Wang
AU - Vivienne Wild
PY - 2026
DA - 2026/09/14
PB - arXiv
DO - 10.48550/arxiv.2609.16187
UR - https://arxiv.org/abs/2609.16187
AB - 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≳4. Their disc-to-total ratio and triaxiality tracks are indistinguishable until z≈ 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_star≈ 10^10.6 M_⊙. 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.
ER -