Collaborative Research: Hyper Suprime-Cam Wide Emission-Line Survey

再电离时期，即星系间气体从中性和不透明状态转变为高度电离状态，也就是透明状态，是宇宙演化的关键时期。确定红移发生时的红移和电离星系间气体的光子的来源代表了观测宇宙学当前的前沿之一。最近在识别高红移星系群方面取得的巨大进展，特别是莱曼α发射星系，有可能回答这个过程何时发生的问题。该项目将开发大型、均匀的星系样本，以确定高红移超亮星系的特性。该项目的一个重要方面是为研究生和本科生提供研究机会，以激发他们的兴趣并鼓励他们参与科学，培训他们使用观测方法和仪器，指导他们使用大型成像和光谱数据集的计算机处理和还原技术，并提供指导，特别强调鼓励女学生。观测表明，高红移的莱曼α发射器（LAE）分数在红移7之后下降，这被解释为标志着在这个红移处再电离的开始。然而，最明亮的LAEs似乎没有表现出这样的演变，并且可能比低光度LAEs表现出更复杂的谱线轮廓，这表明最明亮的LAEs通过产生高电离环境来保护自己免受IGM演变的中性。因此，可以直接看到星系，而不会被周围的星系间介质散射。本次调查的目的是利用斯巴鲁望远镜上的super super - cam对一个120平方度的中等深度的视场进行观测，以开发一个均匀选择的非常明亮的LAEs样本，以及一个非常大的中等亮度LAEs样本，从中我们可以确定LAEs从红移5到红移7的性质。从这些样品中，研究人员将能够确定LAEs如何依赖于环境和红移范围内的光度，以及估计最亮LAEs中电离光子的产生和HII孔隙度的增长。确定再电离边界附近星系的性质，特别是它们的电离光子产生，将为星系间气体演化、星系演化和高红移结构形成的理论模型提供强有力的约束。

The epoch of reionization, when the intergalactic gas went from being neutral and opaque to being very highly ionized, and therefore transparent, is a key period in the evolution of the Universe. Determining the redshift when this occurred and the sources of the photons that ionized the intergalactic gas represents one of the current frontiers in observational cosmology. The enormous recent progress in identifying populations of high-redshift galaxies, particularly the Lyman alpha emitting galaxies, has the potential to answer the question of when this process occurred. This project will develop large, homogeneous galaxy samples with which to determine the properties of the ultra-luminous galaxies at high redshift. An important aspect of this project is to provide research opportunities for graduate and undergraduate students that will engage their interest and encourage their participation in science, train them in observational methods and instruments, direct them in computer processing and reduction techniques for large imaging and spectroscopic data sets, and provide mentoring, with a particular emphasis on encouraging women students. Observations suggesting a drop in the high-redshift Lyman Alpha Emitter (LAE) fraction beyond a redshift of seven have been interpreted as marking the onset of reionization at this redshift. However, the most luminous LAEs do not appear to show such an evolution and may also exhibit more complex line profiles than lower-luminosity LAEs, suggesting that the most luminous LAEs are protecting themselves from the evolving neutrality of the IGM by generating highly ionized surroundings. As a consequence, the galaxy can be seen directly without scattering from the surrounding intergalactic medium. The aim of the proposed survey is to observe a 120 square degree field to moderate depth using Hyper Suprime-Cam on the Subaru telescope in order to develop a large uniformly-selected sample of very luminous LAEs, as well as a very large sample of more moderate-luminosity LAEs from which we can determine the properties of LAEs from redshift 5 to redshift 7. From these samples, the researchers will be able to determine how LAEs depend on environment and luminosity in this redshift range, as well as estimate the ionizing photon production in the most luminous LAEs and the growth of HII porosity. Determining properties of galaxies near the reionization boundary, and particularly their ionizing photon production, will provide strong constraints on theoretical models of the evolution of the intergalactic gas, the evolution of galaxies, and structure formation at high redshift.