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

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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.