发表机构
University of California, Los Angeles; Shanghai Jiao Tong University; University of Kentucky; University of California, Riverside; University of California, Davis; University of Chicago; Kavli Institute for Cosmological Physics, University of Chicago（加州大学洛杉矶分校; 上海交通大学; 肯塔基大学; 加州大学河滨分校; 加州大学戴维斯分校; 芝加哥大学; 卡弗里宇宙物理学研究所，芝加哥大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
基于AURORA巡天58个恒星形成星系的JWST/NIRSpec数据，确定恒星连续谱荧光是OI λ8449发射的主要产生机制，复合、碰撞激发和Lyβ荧光贡献可忽略。
AI 中文摘要
我们分析了AURORA巡天中58个恒星形成星系（红移1.3<z<4.8）的深度JWST/NIRSpec观测数据，以研究允许的OI λ8449发射线的起源。基于在未探测到该线的天体叠加光谱中检测到OI λ8449，我们推断该特征在恒星形成星系中普遍存在，其强度约为Hα的0.5%。我们还将结果与CHAOS巡天中本地HII区以及DESI巡天中z<0.1619的恒星形成星系中该谱线的测量结果进行了比较，发现这些天体中的OI λ8449相对于Hα的强度相似。我们评估了四种产生机制：复合、碰撞激发、Lyβ荧光和恒星连续谱荧光。在这些机制中，基于额外探测到近红外OI λ11290和OI λ13168发射线，恒星连续谱荧光（而非Lyβ荧光）为OI λ8449发射提供了最具说服力的解释。采用由叠加复合光谱推导出的物理条件，我们预测了其他机制对OI λ8449的贡献，确定复合、碰撞激发和Lyβ荧光对该特征贡献可忽略。虽然使用Cloudy的简单HII区模型能重现AURORA样本中平均观测到的OI λ8449/Hα比值，但未来专注于改进模型密度分布的研究将是更好地解释近红外OI发射线强度的有价值步骤。
英文摘要
We analyze deep JWST/NIRSpec observations of 58 star-forming galaxies at $1.3< z <4.8$ in the AURORA survey to investigate the origin of the permitted OI $λ8449$ emission feature. Based on the detection of OI $λ8449$ in a stack of objects with non-detections, we infer that this feature is ubiquitous among star-forming galaxies at $\sim$0.5% the strength of H$α$. We additionally compare our results with measurements of this line in local HII regions from the CHAOS survey and star-forming galaxies at $z<0.1619$ in the DESI survey, finding a similar strength of OI $λ8449$ relative to H$α$ in these objects. We evaluate four production mechanisms: recombination, collisional excitation, Ly$β$ fluorescence, and stellar continuum fluorescence. Of these mechanisms, stellar continuum fluorescence (rather than Ly$β$ fluorescence) provides the most compelling explanation for the OI $λ8449$ emission based on the additional detection of the near-infrared OI $λ11290$ and OI $λ13168$ emission lines. Adopting physical conditions derived from a stacked composite spectrum, we make predictions for the contribution of the other mechanisms to OI $λ8449$, determining that recombination, collisional excitation, and Ly$β$ fluorescence contribute negligibly to this feature. While a simple HII region model using Cloudy reproduces the average observed OI $λ8449$/H$α$ ratios in the AURORA sample, future works focused on refining model density profiles will be a valuable step in better explaining the near-infrared OI emission-line strengths.
Comments24 pages, 7 figures, submitted to ApJ
