C3PO：一个红移z≈9的莱曼α发射星系
C3PO: A Lyα Emitting Galaxy at $z \sim 9$
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中文总结 AI 辅助
本研究借助JWST的NIRSpec数据，确认红移z≈9的星系C3PO-8447为第三个高红移莱曼α发射星系，发现其为单一天体驱动的小型电离泡，为早期宇宙再电离研究提供了关键样本。
中文摘要 AI 辅助
我们呈现了对已知红移z=8.99781的星系C3PO-8447的深度观测，观测时长超过10小时，使用的是詹姆斯·韦布空间望远镜（JWST）的近红外光谱仪（NIRSpec）的G140M和G395M模式。我们来自Carbon-3 plus Oxygen（C3PO）巡天的新NIRSpec数据探测到了莱曼α（Lyα）发射，其逃逸分数为1.5±0.3%，速度偏移为210±80 km s⁻¹，这使得C3PO-8447成为第三个被确认的红移z≥9的莱曼α发射星系。该星系具有2.2±0.1×10⁷ M☉的低恒星质量、1.6±0.2 Myr的年轻恒星年龄，以及12+log(O/H)=7.50±0.08的低氧丰度。结合C IV、O III]和C III]发射线的紫外诊断图表明，C3PO-8447的电离由近期的恒星暴增主导。C3PO-8447的低莱曼α逃逸分数意味着它位于一个半径R≈0.07至0.20 pMpc的小型电离泡中，该电离泡可由C3PO-8447单独产生。我们未发现C3PO-8447周围存在大规模星系过密区的证据，也未发现附近星系对其电离光子预算有显著贡献的证据。综合这些结果，表明C3PO-8447可能代表了宇宙再电离早期阶段由一个低质量、剧烈恒星形成星系驱动的电离泡。
英文摘要
We present deep, $>10$ hr, JWST NIRSpec G140M and G395M observations of a previously known galaxy C3PO-8447 at $z=8.99781$. Our new NIRSpec data from the Carbon-3 plus Oxygen (C3PO) survey detect Ly$α$ emission with an escape fraction of $1.5\pm0.3\%$ and a velocity offset of $210\pm80$ km s$^{-1}$, making C3PO-8447 the third Ly$α$ emitting galaxy confirmed at $z\gtrsim 9$. The galaxy has a low stellar mass of $2.2\pm0.1\times 10^7\ M_\odot$, a young stellar age of $1.6\pm0.2$ Myr, and a low oxygen abundance of $12+\log(\mathrm{O/H}) = 7.50\pm0.08$. UV diagnostic diagrams incorporating the C IV, O III], and C III] emission lines indicate that the ionization of C3PO-8447 is dominated by the recent starburst. The low Ly$α$ escape fraction of C3PO-8447 implies that C3PO-8447 resides in a small ionized bubble with radius $R \sim 0.07$ to 0.20 pMpc, which can be produced by C3PO-8447 alone. We find no evidence for either a large-scale galaxy overdensity around C3PO-8447 or a significant contribution from nearby galaxies to its ionizing photon budget. Taken together, these results suggest that C3PO-8447 likely represents an ionized bubble powered by a single low-mass, vigorously star-forming galaxy during the early stages of cosmic reionization.
发表机构
- Texas A&M University（德州农工大学）
- George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University（乔治·P和辛西娅·伍兹基础物理与天文学研究所，德州农工大学）
- Astrophysics Science Division, NASA Goddard Space Flight Center（NASA戈达德太空飞行中心天体物理学科学部）
- Space Telescope Science Institute（空间望远镜科学研究所）
- Center for Space Sciences and Technology, UMBC（UMBC空间科学与技术中心）
- Department of Astronomy, The University of Texas at Austin（德克萨斯大学奥斯汀分校天文学系）
- Cosmic Frontier Center, The University of Texas at Austin（德克萨斯大学奥斯汀分校宇宙前沿中心）
- Department of Astronomy and Astrophysics, The Pennsylvania State University（宾夕法尼亚州立大学天文学与天体物理学系）
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