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

Jonathan Pober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。这个项目包括观察宇宙中第一个星系的形成。这一宇宙历史时期被称为再电离时代（EoR），发生在第一个星系的辐射反馈到星系间介质（IGM）并电离它的时候。该研究员是美国国家科学基金会资助的探测再电离时代的精密阵列（PAPER）的开发者，这是一个检测EoR射电信号的实验。最终，从EoR和其他时代对21cm射电发射的测量提供了一个独特的三维宇宙探测器，它有可能彻底改变我们对宇宙学的理解，就像宇宙微波背景在过去20年里所做的那样。到目前为止，像PAPER这样的实验受到了21cm宇宙信号固有的微弱，以及明显更亮的天体物理学前景发射的限制。这个项目将受益于基础设施和数据分析的最新发展，以克服这些障碍，它可能会提供第一个有意义的约束，对星系的性质负责再电离来自21厘米线的观测。由于PAPER的第一代结果将是低信噪比的，研究员将通过研究21cm EoR实验的系统效应来支持他的主要分析，以最大限度地提高这些测量的科学影响。他与华盛顿大学的赞助科学家Miguel Morales合作，将提供来自Murchison Widefield阵列（MWA）的数据，MWA是另一个旨在检测EoR信号的阵列。这个项目更广泛的影响包括一个重要的教育组成部分。该研究员将接管伽玛射线爆发全天光谱仪实验（GASE）的开发，这是该计划教育部分的独特资源。GASE是一种干涉仪，用于探测来自伽马射线暴（GRB）的低频（30mhz）无线电发射。GASE目前由一组社区大学转学生委托，作为国家科学基金会职业奖（AST-0847753）的一部分招募和培训。这些学生在转学之前就开始了GASE的工作，因此，他们建立了一个支持和指导关系的网络，以帮助对抗“转学冲击”，提高他们的保留率。该研究员将接管GASE项目的指导，并成为这些学生的主要导师。他还将领导他们开发GASE系统，包括一个新的相关器，以实现连续观测。该研究员对该项目的最终愿景是，GASE可以在多个机构中部署，并成为一个实用的、以教育为重点的干涉仪，直到最近，大多数本科物理和天文学院系都无法实现。

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.