发表机构
University of Washington; KAIST; The University of Texas at Austin; University of California, Santa Barbara; Cosmic Dawn Center (DAWN); University of Pittsburgh（华盛顿大学; 韩国科学技术院; 德克萨斯大学奥斯汀分校; 加州大学圣塔芭芭拉分校; 宇宙黎明中心; 匹兹堡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过JWST光谱叠加分析274个z=2-5星系，首次统计证明静止星系普遍存在过量中性气体外流，且外流可能由非恒星反馈（如AGN）驱动。
AI 中文摘要
星系表现出广泛的恒星形成活动，从活跃恒星形成到静止系统。然而，导致恒星形成快速停止和持续抑制的机制仍然知之甚少，特别是对于JWST在$z>3$处最近发现的静止星系。中性气体外流提供了静止星系中气体移除和调节的直接示踪。因此，我们利用JWST/NIRSpec中分辨率光栅光谱和NIRCam测光，对来自DAWN JWST档案（DJA）和EMBER JWST计划的274个$z=2$--5星系进行了NaID $\lambda\lambda5891,5897$吸收线叠加分析。在所有跨越$z=2$--5的静止星系叠加中均探测到NaID吸收，提供了首个统计证据表明中性气体外流是早期宇宙静止星系的普遍特征。与非静止星系叠加相比，静止叠加显示质量加载因子高出2--4个数量级，质量外流率$\dot{M}_{\rm out} \sim 9$--$30\\,M_\odot\\,{\rm yr}^{-1}$高出约$\sim0.5$--$1$个数量级，外流速度$v_{\rm out} \sim 310$--$570\\,{\rm km\\,s}^{-1}$高出约$\sim2$倍。极端的质量加载因子值和下降的恒星形成历史强烈表明，这些外流不能仅由当前恒星形成驱动。在统计可靠的$2 \leq z < 3$和$3 \leq z < 4$静止红移区间内，升高的$[\mathrm{N\\,II}]/\mathrm{H}\alpha$和$[\mathrm{O\\,III}]/\mathrm{H}\beta$比值与可能的AGN贡献一致，表明非恒星反馈可能在这些时期的星系维持静止状态中发挥作用。
英文摘要
Galaxies exhibit a broad range of star formation activity, from actively star-forming to quiescent systems. Yet, the mechanisms responsible for the rapid shutdown and continued suppression of star formation remain poorly understood, particularly for the quiescent galaxies recently uncovered by JWST at $z>3$. Neutral gas outflows provide a direct tracer of gas removal and regulation in quiescent galaxies. We therefore present a NaID $λ\lambda5891,5897$ absorption--line stacking analysis of 274 galaxies at $z=2$--5 drawn from the DAWN JWST Archive (DJA) and the EMBER JWST program, using JWST/NIRSpec medium-resolution grating spectroscopy and NIRCam photometry. NaID absorption is detected in all quiescent galaxy stacks spanning $z=2$--5, providing the first statistical evidence that neutral gas outflows are a ubiquitous feature of quiescent galaxies in the early Universe. Compared to the non-quiescent galaxy stacks, the quiescent stacks show mass loading factors higher by 2--4 dex, with mass outflow rates $\dot{M}_{\rm out} \sim 9$--$30\,M_\odot\,{\rm yr}^{-1}$ elevated by $\sim0.5$--$1$ dex and outflow velocities $v_{\rm out} \sim 310$--$570\,{\rm km\,s}^{-1}$ higher by a factor of $\sim2$. The extreme mass loading factor values and declining star formation histories strongly indicate that these outflows cannot be driven by current star formation alone. In the statistically reliable quiescent redshift bins at $2 \leq z < 3$ and $3 \leq z < 4$, the elevated $[\mathrm{N\,II}]/\mathrm{H}α$ and $[\mathrm{O\,III}]/\mathrm{H}β$ ratios are consistent with a possible AGN contribution, suggesting that non-stellar feedback may play a role in sustaining quiescence in galaxies at these epochs.
Comments30 pages, 12 figures, 9 tables; submitted to ApJ
