21cm Cosmology: Probing the Epoch of Reionization

Aaron Parsons
(UC Berkeley)


The Epoch of Reionization (EoR)--the rapid ionization of the majority of the hydrogen in the universe by the light of the first stars and supermassive black holes--is perhaps the last major phase transition of our universe that remains unexplored. First-generation experiments aiming to measure the 3-dimensional power spectrum of reionization fluctuations via redshifted 21cm emission are currently underway. While calibration, foreground removal, and obtaining the requisite sensitivity are all challenging aspects of these efforts, early results suggest that there any imminently be a detection that significantly impacts our understanding of the dominant processes at work during this era.

I will discuss current prospects for detecting the 21cm EoR signal in the context of our recent progress with 16- and 32- antenna deployments of the Precision Array for Probing the Epoch of Reionization (PAPER) in Green Bank, West Virginia, and the Karoo Desert of South Africa. I will also discuss a novel technique for accessing the 3-dimensional power spectrum of reionization, and the impacts of systematics and foregrounds on recent measurements Finally, I will present our current plans for the Hydrogen Epoch of Reionization Array (HERA) that will supersede all current efforts and enable the direct imaging of reionization structures.