JWST PRIMER: strong evidence for the environmental quenching of low-mass galaxies out to z ≃ 2

Hamadouche, M L; McLure, R J; Carnall, A C; McLeod, D J; Dunlop, J S; Whitaker, K E; Donnan, C T; Begley, R; Stanton, T M; Almaini, O; Aird, J; Cullen, F; Cutler, S; Grogin, N A; Koekemoer, A M

Abstract

We present the results of a study investigating the galaxy stellar-mass function (GSMF), size-mass relations and morphological properties of star-forming and quiescent galaxies over the redshift range 0.25 < z < 2.25, using the JWST PRIMER survey. The depth of the PRIMER near-IR imaging allows us to confirm the double Schechter function shape of the quiescent GSMF out to z ≃ 2.0, via a clear detection of the upturn at log 10 (M ⋆ /M ⊙) ≤ 10 thought to be induced by environmental quenching. Additionally, we confirm that quiescent galaxies can be split into separate populations at log 10 (M ⋆ /M ⊙) ≃ 10, based on their size-mass relations and morphologies. We find that low-mass quiescent galaxies have more disk-like morphologies (based on Sérsic index, Gini coefficient and M 20 metrics) and follow a shallower size-mass relation than their high-mass counterparts. Indeed, the slope of the size-mass relation followed by low-mass quiescent galaxies is indistinguishable from that followed by star-forming galaxies, albeit with a lower normalization. Moreover, within the errors, the evolution in the median size of low-mass quiescent galaxies (R e ∝ (1 + z) −0.22±0.10) is indistinguishable from that followed by star-forming galaxies, and significantly less rapid than that displayed by high-mass quiescent galaxies (R e ∝ (1 + z) −1.48±0.16). Overall, our results are consistent with low and high-mass quiescent galaxies following different quenching pathways. The evolution of low-mass quiescent galaxies is qualitatively consistent with the expectations of external/environmental quenching (e.g. ram-pressure stripping). In contrast, the evolution of high-mass quiescent galaxies is consistent with internal/mass quenching (e.g. AGN feedback) followed by size growth driven by minor mergers.

Citation

Hamadouche, M. L., McLure, R. J., Carnall, A. C., McLeod, D. J., Dunlop, J. S., Whitaker, K. E., Donnan, C. T., Begley, R., Stanton, T. M., Almaini, O., Aird, J., Cullen, F., Cutler, S., Grogin, N. A., & Koekemoer, A. M. (2025). JWST PRIMER: strong evidence for the environmental quenching of low-mass galaxies out to z ≃ 2. Monthly Notices of the Royal Astronomical Society, https://doi.org/10.1093/mnras/staf971

• Journal Article Type: Article
• Acceptance Date: Jun 5, 2025
• Online Publication Date: Jun 13, 2025
• Publication Date: Jun 13, 2025
• Deposit Date: Jun 13, 2025
• Publicly Available Date: Jun 13, 2025
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1093/mnras/staf971
• Public URL: https://nottingham-repository.worktribe.com/output/50175459
• Publisher URL: https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/staf971/8161688