Colloquium: Prof. Hy Trac

Prof. Hy Trac
Department of Physics
Carnegie Mellon University

Friday Nov 14, 4:00–5:00pm, 211 Witmer Hall. Refreshments at 3:30pm.

Cosmic Reionization: How the First Galaxies Lit Up the Universe

Cosmic reionization is a milestone event whereby the first generation of stars, galaxies, and quasars photo-ionized and photo-heated the hydrogen gas by the time the Universe was about a billion years old. How and when did the epoch of reionization (EoR) effectively begin and end are still highly uncertain. Ongoing observations of high-redshift galaxies, the cosmic microwave background (CMB), and 21cm radiation will help address the many open questions. On the theoretical front, I will present a new project called SCORCH (Simulations and Constructions of the Reionization of Cosmic Hydrogen) that will provide theoretical tools to facilitate more accurate comparisons with observations. I use RadHydro simulations that simultaneously evolve the dark matter, baryons, and radiation to show that higher-density regions tracing the large-scale structure are generally reionized earlier than lower-density regions far from sources. Using a novel method to construct mock observations on Gigaparsec scales, I quantify and discuss the imprints of patchy reionization on the CMB and 21cm radiation.