"How to Reionize the Universe: Lessons from Low Redshift"

The reionization of the intergalactic medium (IGM) at z > 6 is one of the major transformations in the universe’s history, but we do not yet know which galaxies were responsible for this event. Unfortunately, IGM absorption prevents us from directly measuring escaping ionizing Lyman continuum (LyC) photons from z>6 galaxies. Instead, we must investigate LyC escape using lower-redshift samples. To address this issue, we have undertaken the Low-redshift Lyman Continuum Survey, the largest survey of LyC emission at low redshift. With HST UV observations of 66 galaxies, this survey has nearly tripled the number of low-redshift LyC detections, enabling us to systematically test proposed indirect diagnostics of LyC and establish the physical properties of LyC-emitting galaxies. I will share recent results from the survey, which is giving us new insights into feedback and the interstellar medium in highly star-forming galaxies and revealing the possible properties of the galaxies that reionized the Universe.