First Science from the Epoch of Reionization with the 21cm Line

乔纳森·波伯博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在华盛顿大学开展研究和教育项目。这个项目包括观测，以了解宇宙中第一批星系的形成。这段宇宙历史被称为再电离时代(EoR)，当第一批星系的辐射反馈到星际介质(IGM)并将其电离时，就发生了这一时期。这位研究员是美国国家科学基金会资助的用于探测再电离纪元的精密阵列(论文)的开发人员，这是一项检测EOR无线电信号的实验。最终，对EOR和其他历元的21厘米射电辐射的测量提供了一个独特的三维宇宙探测器，有可能像过去20年的宇宙微波背景所做的那样，彻底改变我们对宇宙学的理解。到目前为止，像纸这样的实验一直受到宇宙学21厘米信号固有的微弱和更明亮的天体物理前景发射的存在的限制。该项目将受益于基础设施和数据分析方面的最新发展，以克服这些障碍，并可能通过对21厘米线的观测，对负责再电离的星系的性质提供第一个有意义的约束。由于论文的第一代结果将是低信噪比，这位研究员将通过一项运动来支持他的主要分析，以调查21厘米提高采收率实验的系统效应，以最大限度地发挥这些测量的科学影响。他与华盛顿大学赞助科学家米格尔·莫拉莱斯的合作将提供对Murchison Widefield阵列(MWA)数据的访问，MWA是另一个目标是探测EOR信号的阵列。该项目的更广泛影响包括一个重要的教育部分。这位研究员将接管伽马射线暴全天空能谱仪实验(GASE)的开发，这是该计划教育部分的一个独特资源。GASE是一种干涉仪，设计用于探测伽马射线暴(GRB)的低频(30 MHz)射电发射。GASE目前正由一个社区大学转学学生团队委托，作为国家科学基金会职业奖项(AST-0847753)的一部分进行招募和培训。这些学生在转学之前就开始从事GASE的工作，因此，他们建立了一个支持和指导关系网络，以帮助对抗“转学冲击”，并提高他们的保留率。这位研究员将接管GASE项目的指导工作，并担任这些学生的主要导师。他还将领导他们开发GASE系统，包括一种新的相关器，以实现连续观测。这位研究员对该项目的最终愿景是，GASE可以在多个机构部署，并成为一台动手操作、专注于教育的干涉仪，直到最近，它还超出了大多数本科生物理和天文学系的能力范围。

Dr. Jonathan Pober is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Washington. This project involves observations to understand the formation of the first galaxies in the Universe. This period of cosmic history, called the Epoch of Reionization (EoR), occurred when emission from the first galaxies fed back into the intergalactic medium (IGM) and ionized it. The Fellow is a developer of the NSF-funded Precision Array for Probing the Epoch of Reionization (PAPER), an experiment to detect a radio signal from the EoR. Ultimately, measurements of 21cm radio emission from both the EoR and other epochs offer a unique, 3-dimensional cosmic probe with the potential to revolutionize our understanding of cosmology as the cosmic microwave background has done in the past two decades.Experiments like PAPER have been limited so far by the intrinsic faintness of the cosmological 21cm signal, and the presence of significantly brighter astrophysical foreground emission. This project will benefit from recent developments in infrastructure and data analysis to overcome these obstacles, and it may offer the first meaningful constraints on the nature of the galaxies responsible for reionization to come from observations of the 21cm line. Because the first generation of results from PAPER will be low signal-to-noise, the Fellow will support his principal analysis with a campaign to investigate systematic effects in 21cm EoR experiments to maximize the scientific impact of these measurements. His collaboration with sponsoring scientist Miguel Morales at the University of Washington will provide access to data from the Murchison Widefield Array (MWA), another array targeting a detection of the EoR signal. The broader impacts of this project include a significant educational component. The fellow will take over the development of the Gamma-ray Burst All-Sky Spectrometer Experiment (GASE), a unique resource for the educational component of this program. GASE is an interferometer designed to detect low-frequency (30 MHz) radio emission from a gamma-ray burst (GRB). GASE is currently being commissioned by a team of community college transfer students, recruited and trained as part of an NSF CAREER award (AST-0847753). These students begin working on GASE prior to transferring, and as a result, they develop a network of support and mentoring relationships to help fight against "transfer shock" and increase their retention rate. The fellow will take over direction of the GASE project and be the principal supervisor for these students. He will also lead them to develop the GASE system, including a new correlator to enable continuous observations. The fellow's ultimate vision for the project is for GASE to be deployable at multiple institutions and for it to be a hands-on, education-focused interferometer that until recently was beyond the reach of most undergraduate physics and astronomy departments.