发表机构
University of California, Los Angeles; INAF - OAS, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna; Università degli Studi di Ferrara; Università degli Studi di Milano（加州大学洛杉矶分校; 意大利国家天体物理研究所-博洛尼亚天文与空间科学观测站; 费拉拉大学; 米兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用JWST NIRSpec IFU观测被Abell 2744高度放大的极暗源SALSA（$z=5.66$），测量其发射线，发现高电离效率、低金属丰度及高Ly$\alpha$逃逸分数，揭示再电离纪元暗源极端性质。
AI 中文摘要
我们展示了 JWST NIRSpec IFU 对已知最暗（M$_{UV}>-13.6$）的电离源之一在 $z=5.66$ 处的光谱测量结果，该源被称为小且被透镜化的源弧（SALSA）。该源被透镜星系团 Abell 2744 高度放大（$\mu>100$），为研究再电离纪元中暗源的物理性质提供了独特机会。我们利用静止系紫外和光学发射线表征 SALSA 的星云发射，并研究其电离效率、星云激发和化学增丰之间的关系。我们稳健地探测到 H$\alpha$ 发射，并利用它预测 H$\beta$ 通量，假设尘埃消光可忽略。我们还测量了 [OIII]$\lambda$5007 发射，并估算氧丰度，得到高 R3 指数 $2.82_{-0.25}^{+0.34}$ 和相对较低的金属丰度 $\mathrm{12+log(O/H)}= 7.43\pm0.09$。SALSA 呈现出高电离产生效率 log$(\xi_{ion})=25.49_{-0.08}^{+0.09}$ Hz erg $^{-1}$，与来自大质量恒星和恒定恒星形成率的理论模型一致，以及高 Ly$\alpha$ 逃逸分数 $f_{\mathrm{esc}}^{\mathrm{Ly}\alpha}=0.39\pm0.14$。这些性质使 SALSA 跻身于该纪元已知最极端的恒星形成源之列。
英文摘要
We present JWST NIRSpec IFU spectroscopic measurements of one of the faintest (M$_{UV}>-13.6$) known ionizing sources at $z=5.66$, dubbed Small And Lensed Source Arc, SALSA. This source is highly magnified ($μ>100$) by the lensing galaxy cluster Abell 2744, providing a unique opportunity to investigate the physical properties of faint sources in the Epoch of Reionization. We characterize SALSA's nebular emission using rest-frame UV and optical emission lines and investigate the relationship between its ionizing efficiency, nebular excitation, and chemical enrichment. We robustly detect H$α$ emission and use it to predict the H$β$ flux assuming negligible dust attenuation. We also measure the [OIII]$λ$5007 emission and estimate oxygen abundance resulting in a high R3 index $2.82_{-0.25}^{+0.34}$ and relatively low metallicity $\mathrm{12+log(O/H)}= 7.43\pm0.09$. SALSA presents a high ionizing production efficiency log$(ξ_{ion})=25.49_{-0.08}^{+0.09}$ Hz erg $^{-1}$, consistent with theoretical models from very massive stars and constant star formation rate, and a high Ly$α$ escape fraction $f_{\mathrm{esc}}^{\mathrm{Ly}α}=0.39\pm0.14$. These properties place SALSA among the most extreme star-forming sources known at this epoch.
CommentsSubmitted to ApJL. 8 pages, 4 figures, 1 table
