Joint Astrophysics Colloquium

What Can Galaxies Tell Us About Reionization?

Charlotte Mason

Harvard-Smithsonian Astrophysical Observatory

The reionization of intergalactic hydrogen in the universe's first billion years was likely driven by the first stars and galaxies, which we cannot detect directly. The timeline of reionization is currently uncertain but if it is accurately measured it can unveil properties of first light' sources. I will describe how we can use galaxies at our current observational frontiers to learn about reionization. In particular, Lyman alpha (Lyα) emission from galaxies can probe the intergalactic medium at high redshift, but requires modeling physics from pc to Gpc scales. I will present current constraints on reionization from observations of galaxies, focusing on Ly-alpha observations at z>6 using a multi-scale forward-modelling approach, and describe future prospects with JWST.