发表机构
Tufts University; Ben-Gurion University of the Negev; University of Toronto; Space Telescope Science Institute; The Johns Hopkins University; The University of Texas at Austin（塔夫茨大学; 内盖夫本-古里安大学; 多伦多大学; 太空望远镜科学研究所; 约翰斯·霍普金斯大学; 德克萨斯大学奥斯汀分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过引力透镜实现亚100 pc分辨率，研究了一个z~5的大质量宁静星系，发现其淬灭无需压实或活动星系核，挑战了现有理论模型。
AI 中文摘要
最近的詹姆斯·韦伯太空望远镜光谱巡天揭示了在宇宙诞生最初十亿年内快速组装的早期星系的大量存在。宇宙学模拟难以重现这一星系族群，因为模型要求在早期宇宙中，重子向恒星的转换需快速且高效，随后恒星形成突然终止，即所谓的“淬灭”。由于高红移场星系看起来致密且无法分辨，检验这些理论模型仍然困难。这种分辨率的缺乏使得无法区分由压实驱动的淬灭与长期演化。在此，我们呈现VENUS-CLJ0152-QG1，一个位于$z=5.18\pm0.15$的大质量后星暴星系，推断其在过去3000万年内具有低水平的恒星形成。前景星系团CL J0152.7-1357通过引力透镜将该系统成像为三个像，中位放大率分别为$\mu\sim$ 7、11和0.6。这种几何结构产生了约70 pc的物理分辨率，比JWST/NIRCam的基本模糊极限（在$z\sim5$时半高全宽约为0.48 kpc）好约7倍。我们的二维成图揭示了一个比预期大两倍的半光半径，中心恒星质量面密度比场类比星系低半个数量级，以及偏离中心的电离气体发射。这些特征共同表明，VENUS-CLJ0152-QG1在没有压实事件或明显活动星系核的情况下突然停止了恒星形成。因此，该星系表明，无法分辨的观测可能高估了早期星系的整体密度，且理论模型需要替代途径来淬灭大质量星系，而不依赖于压实或未被遮挡的活动星系核。
英文摘要
Recent James Webb Space Telescope spectroscopic surveys reveal an abundance of rapidly assembled early galaxies in the first billion years. Cosmological simulations struggle to reproduce this population because models require a rapid, highly efficient conversion of baryons into stars followed by an abrupt cessation of star-formation, known as quenching, in the early Universe. Testing these theoretical models remains difficult because high-redshift field galaxies appear compact and unresolved. This lack of resolution makes it impossible to distinguish compaction-driven quenching from secular evolution. Here we present VENUS-CLJ0152-QG1, a massive post-starburst galaxy at $z=5.18\pm0.15$, with inferred low-levels of star-formation in the last 30 Myr. The foreground cluster CL J0152.7-1357 gravitationally lenses the system into three images with median magnifications of $μ\sim$ 7, 11, and 0.6. This geometry yields a physical resolution of $\sim 70$ pc, a factor of $\sim 7$ better than the JWST/NIRCam fundamental blurring limit (full-width half-maximum of $\sim$0.48 kpc at $z\sim5$). Our two-dimensional mapping reveals a half-light radius twice as large as expected, a central stellar mass surface density half a dex lower than field analogs, and off-center ionized gas emission. Together, these features show that VENUS-CLJ0152-QG1 abruptly ceased star formation in the absence of a compaction event or an obvious active galactic nucleus. Consequently, this galaxy shows that unresolved observations likely overestimate the global densities of early galaxies, and that theoretical models require alternative pathways to quench massive sources without relying on compaction or unobscured AGN.
Comments30 pages, 6 figures, 1 table, submitted to Nature Astronomy
