发表机构
Pontificia Universidad Católica de Chile; Millennium Nucleus for Galaxies (MINGAL); Las Campanas Observatory, Carnegie Institution of Washington; Universidad Diego Portales; University of Washington; University of California, Santa Barbara; Cosmic Dawn Center (DAWN); Imperial College London; International Centre for Radio Astronomy Research (ICRAR), University of Western Australia; Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM; Space Telescope Science Institute（智利天主教 Pontificia 大学; 银河系千年核团（MINGAL）; 卡内基华盛顿机构拉斯坎帕纳斯天文台; 迭戈·波特莱斯大学; 华盛顿大学; 加州大学圣巴巴拉分校; 宇宙黎明中心（DAWN）; 伦敦帝国理工学院; 西澳大利亚大学国际射电天文研究中心（ICRAR）; 巴黎萨克雷大学、巴黎西岱大学、CEA、CNRS、AIM; 太空望远镜科学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过 ALMA 的 Ex-MORA 巡天开展 $0.5<z<5$ 范围的分子气体线搜寻，探测到 52 个星系，揭示了不同演化阶段星系的气体性质，证明广域线搜寻可有效获取大质量气体储库。
AI 中文摘要
当前对星际介质中冷气体的研究存在选择偏差，因为光学/近红外巡天倾向于大质量、低遮蔽的星系，而遗漏了富气体的被动或恒星形成效率低的系统。要克服这一问题，需要通过分子气体而非恒星光度选择的大体积线巡天。我们利用扩展重电离遮蔽测绘巡天（Ex-MORA）的 ALMA 4 波段观测，在红移 $0.5 < z < 5$ 范围内开展分子气体普查，覆盖面积为 577 平方角分。结合对明亮发射体的无偏搜寻与利用光谱红移先验的定向搜寻，我们在 CO 或 \textit{[C I]} 跃迁中探测到 52 个星系（其中 2 个显示两条谱线）。通过 \texttt{CIGALE} 软件结合非参数恒星形成历史推导物理性质，利用与金属丰度相关的转换因子估算气体质量。该样本以主序（MS）星系为主，具有高恒星质量（中位数 $\text{log}\text{ }M_*/\text{M}_\text{\textcircled{\raisebox{-0.9pt}{$\bigodot$}}} = 10.83$）和大气体储库（$>10^{10}\text{ }\text{M}_\text{\textcircled{\raisebox{-0.9pt}{$\bigodot$}}}$）。活跃星系群的气体丰度（$\text{$\nu$}_\text{gas}$）随红移增加而上升，不过高红移趋势受 $z \boldsymbol{\text{≈}} 2.4$ 处富气体原星团的影响；而 $z \boldsymbol{\text{≈}} 0.73$ 处的密度区则与场星系群相似。5 个绿谷（GV）星系的气体丰度在宇宙正午达到峰值，表明至少在某些过渡系统中，恒星反馈可能通过加热气体而非快速耗尽气体来抑制恒星形成。高分辨率运动学分析显示旋转盘占主导地位。这些结果表明，广域线搜寻能有效恢复不同演化阶段的大质量气体储库。
英文摘要
Current investigations of cold gas in the interstellar medium face selection biases, as optical/near-infrared surveys favor massive, low-obscuration galaxies and miss gas-rich passive or inefficient star-forming systems. Overcoming this requires large-volume line surveys selected by molecular gas rather than stellar luminosity. We present a molecular gas census across $0.5 < z < 5$ using ALMA Band 4 observations from the Extended Mapping of Obscuration to Reionization Survey (Ex-MORA), covering 577 arcmin$^2$. Combining an unbiased search for bright emitters with a targeted search using spectroscopic redshift priors, we detect 52 galaxies in CO or \ci transitions (two showing two lines). Physical properties were derived via \texttt{CIGALE} with non-parametric star-formation histories, and gas masses were estimated using metallicity-dependent conversion factors. The sample is dominated by main-sequence (MS) galaxies with high stellar masses (median $\log M_*/\text{M}_{\odot} = 10.83$) and large gas reservoirs ($>10^{10}\,\text{M}_{\odot}$). Gas fraction ($μ_{\text{gas}}$) increases with redshift for active populations, though high-redshift trends are influenced by a gas-rich protocluster at $z \approx 2.4$. Conversely, an overdensity at $z \approx 0.73$ mirrors the field population. Five Green Valley (GV) galaxies exhibit a $μ_{\text{gas}}$ peak at cosmic noon, suggesting stellar feedback may suppress star formation by heating gas rather than rapidly depleting it in at least some transitional systems. Resolved kinematics show a prevalence of rotating disks. These results demonstrate that wide-area line searches effectively recover massive gas reservoirs across diverse evolutionary stages
