View My GitHub Profile hchri004@ucr.edu
I recently received my PhD from UC Riverside working with Prof. George Becker on cosmic reionization and the intergalactic medium. Reionization is the last major phase transition in the history of the universe, when the intervening gas between galaxies became ionized and transparent. Understanding how and when reionization ended is important context for our understanding of the first stars and galaxies in the universe. Recent observations have found a large scatter in the opacity of the intergalactic medium, including some very long opaque "troughs", which is unexpected for an ionized IGM and suggests that reionization may end later than previously believed. My research is focused on understanding how and why this scatter occurs. I use Subaru/Hyper Suprime Cam imaging to survey galaxies in the fields surrounding particularly opaque and transmissive quasar sightlines to understand how opacity and density are related to each other during this phase of the universe's history. The opacity-density relation is determined the important physical processes in the intergalactic medium, and understanding it gives us useful insight into how and when reionization ended.
My past research appointments have included REUs at Rutgers University (2015 with Prof. Eric Gawiser) and the Maria Mitchell Observatory (2016 with Dr. Regina Jorgenson) and undergraduate research with Prof. Kristen Larson at Western Washington University. I have experience with wide-field imaging, photometric surveys, and IFU and slit spectroscopy.