JWST PRIMER: post-starburst galaxies dominate the low-mass quiescent galaxy population since z ∼ 2

作者：Thomas de Lisle, David T. Maltby, O. Almaini, Vivienne Wild, Elizabeth Taylor, Kate Rowlands, Guillaume Hewitt, Maya Skarbinski, James S Dunlop, Adam C. Carnall, Anton M. Koekemoer, Norman A. Grogin, D J McLeod · 发表于：Monthly Notices of the Royal Astronomical Society · 年份：2026 · DOI：10.1093/mnras/stag1496 · 研究领域：Galaxies: Formation, Evolution, Phenomena、Astronomy and Astrophysical Research、Stellar, planetary, and galactic studies

ABSTRACT We present the evolution of the stellar mass functions for photometrically-selected star-forming, passive and post-starburst galaxies, based on James Webb Space Telescope PRIMER observations of the Ultra-Deep Survey (UDS) field. We identify over 800 post-starburst galaxies within the redshift range $0.5 \lt z \lt 3.0$. We confirm the presence of a low-mass upturn in the quenched galaxy mass function at $\log (M_{\ast }/\mathrm{M_\odot }) \lt 10$ out to $z\sim 2$, and show it is primarily driven by post-starburst galaxies. These findings imply that a rapid quenching pathway for low-mass galaxies is already active by $z \sim 2$, which may be linked to environmental processes. If we assume that all post-starburst galaxies evolve into passive galaxies, adopting a typical visibility time for the post-starburst phase, we find a significant overprediction of low-mass passive galaxies at later times. We suggest a variety of factors that could contribute to reconciling this tension. If low-mass ($M_{\ast } \lesssim 10^{10}\, \mathrm{{\rm M}_{\odot }}$) post-starburst galaxies quench through slower channels than high-mass systems then the post-starburst phase may be visible for longer periods, reducing their contribution to the passive population. However, the maximum realistic visibility time-scale cannot account for all of the excess. We propose that additional factors inhibit the build-up of the low-mass passive galaxy mass function. These galaxies may be removed through me...