The launch of the James Webb Space Telescope (JWST) in late 2021 marks a new start for studies of galaxy formation at high redshift ( z ≳ 6) during the era of cosmic reionization. JWST can capture sensitive, high-resolution images and multiobject spectroscopy in the IR that will transform our view of galaxy formation during the first billion years of cosmic history. This review summarizes our current knowledge of the role of galaxies in reionizing intergalactic hydrogen ahead of JWST, achieved through observations with the Hubble Space Telescope and ground-based facilities including Keck, the Very Large Telescope, Subaru, and the Atacama Large Millimeter/Submillimeter Array. We identify outstanding questions in the field that JWST can address during its mission lifetime, including with the planned JWST Cycle 1 programs. These findings include the following: ▪ Surveys with JWST have sufficient sensitivity and area to complete the census of galaxy formation at the current redshift frontier ( z ∼ 8–10). ▪ Rest-frame optical spectroscopy with JWST of galaxies will newly enable measures of star-formation rate, metallicity, and ionization at z ∼ 8–9, allowing for the astrophysics of early galaxies to be constrained. ▪ The presence of evolved stellar populations at z ∼ 8–10 can be definitively tested by JWST, which would provide evidence of star formation out to z ∼ 15.

中文翻译：

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星系形成和再电离：关键的未知数和预期突破 作者：詹姆斯·韦伯太空望远镜


詹姆斯韦伯太空望远镜 （JWST） 于 2021 年底发射，标志着在宇宙再电离时代，在高红移 （z ≳ 6） 下研究星系形成的新起点。JWST 可以在 IR 中捕获敏感、高分辨率的图像和多目标光谱，这将改变我们对宇宙历史前 10 亿年星系形成的看法。这篇综述总结了我们目前关于星系在 JWST 之前在星系间氢再电离中的作用的知识，这是通过使用哈勃太空望远镜和地面设施（包括 Keck、甚大望远镜、斯巴鲁和阿塔卡马大型毫米/亚毫米阵列）的观测获得的。我们确定了 JWST 在其任务生命周期内可以解决的现场突出问题，包括计划的 JWST Cycle 1 计划。这些发现包括以下内容：▪使用 JWST 进行的调查具有足够的灵敏度和面积，可以在当前的红移边界 （z ∼ 8-10） 完成星系形成的普查。▪ 使用 JWST 对星系进行静止框架光谱学将新近实现恒星形成速率、金属丰度和 z ∼ 8-9 处电离的测量，从而可以限制早期星系的天体物理学。▪ JWST 可以明确测试 z ∼ 8-10 处演化的恒星群的存在，这将提供 z ∼ 15 范围内恒星形成的证据。