Postdoctoral Fellowship: AAPF: Probing the Cosmic Dawn with the OVRO-LWA

Ruby Byrne is awarded an NSF Astronomy and Astrophysics Fellowship to carry out a program of research and education at the California Institute of Technology. Byrne will use emission from neutral hydrogen to study the Cosmic Dawn, the phase in cosmological history when stars and galaxies first formed. She will also lead a summer research program for high school students and undergraduates that will expose students to astronomical data analysis techniques and prepare them for careers in science. This project employs the OVRO-LWA, a radio array in California’s Owens Valley that operates at frequencies of 12-85 MHz. The upgraded OVRO-LWA Stage III array is sensitive to highly redshifted signals from neutral hydrogen’s 21 cm emission line, which trace the intergalactic medium during the Cosmic Dawn and Epoch of Reionization. Byrne will implement novel precision data analysis techniques to produce three key science results: (1) a measurement of the sky-averaged 21 cm spectrum, (2) the strongest constraints to date on the power spectrum of 21 cm fluctuations during the Cosmic Dawn, and (3) high-fidelity, polarized maps of the low-frequency radio sky. These results will illuminate the dynamics of early galaxy formationmand test models of cosmological evolution. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.