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

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 , using the JWST PRIMER survey. The depth of the PRIMER near-IR imaging allows us to confithe double Schechter function shape of the quiescent GSMF out to , via a clear detection of the upturn at thought to be induced by environmental quenching. Additionally, we confithat quiescent galaxies can be split into separate populations at , based on their size–mass relations and morphologies. We find that low-mass quiescent galaxies have more disc-like morphologies (based on Sérsic index, Gini coefficient, and 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 ( is indistinguishable from that followed by star-forming galaxies, and significantly less rapid than that displayed by high-mass quiescent galaxies (. 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. active galactic nucleus feedback) followed by size growth driven by minor mergers.

Publication
Monthly Notices of the Royal Astronomical Society

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