AI 中文总结
本研究基于JWST PRIMER观测发现，自z~2以来后星暴星系主导低质量静止星系群，低质量 quenched 星系的形成由复杂过程相互作用支配。
AI 中文摘要
我们基于JWST PRIMER对超深空巡天（UDS）天区的观测，呈现了测光选出的恒星形成星系、被动星系及后星暴星系的恒星质量函数演化情况。我们在红移范围0.5 < z < 3.0内识别出超过800个后星暴星系。我们确认了在log(M*/M☉) < 10的低质量端，直至z~2处， quenched星系质量函数存在低质量抬升，且该现象主要由后星暴星系驱动。这些发现表明，低质量星系的快速 quenching 路径在z~2时已活跃，这可能与环境过程相关。若假设所有后星暴星系都会演化成被动星系，并采用后星暴阶段的典型可见时间，我们发现后期低质量被动星系存在显著的过度预测。我们提出多种可调和该矛盾的因素：若低质量（M* < 10^10 M☉）后星暴星系通过比大质量系统更慢的通道 quenching，则后星暴阶段可见时间更长，会减少其在被动星系群中的占比，但最大现实可见时间尺度无法解释全部过剩；还存在额外因素抑制低质量被动星系质量函数的积累，这些星系可能通过并合或潮汐扰动被移除、重新激活并返回恒星形成星系群，或代表随机恒星形成休眠阶段的系统。我们得出结论，低质量 quenched 星系群的形成受复杂过程相互作用支配，无法用简单的单向演化路径解释。
英文摘要
We present the evolution of the stellar mass functions for photometrically selected star-forming, passive and post-starburst galaxies, based on JWST PRIMER observations of the Ultra-Deep Survey (UDS) field. We identify over 800 post-starburst galaxies within the redshift range 0.5 < z < 3.0. We confirm the presence of a low-mass upturn in the quenched galaxy mass function at log(M*/M_sun) < 10 out to z~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~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* < 10^10 M_sun) 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 timescale 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 mergers or tidal disruption, rejuvenate and return to the star-forming population, or represent systems observed during a dormant phase of stochastic star formation. We conclude that the emergence of the low-mass quenched population is likely governed by a complex interplay of processes, and cannot be explained by simple one-way evolutionary pathways.
Comments16 pages, 11 figures, Published in MNRAS
