The Ly α and Continuum Origins Survey. II. The Connection between the Escape of Ionizing Radiation and Ly α Halos in Star-forming Galaxies

Abstract One of the current challenges in galaxy evolution studies is to establish the mechanisms that govern the escape of ionizing radiation from galaxies. Here, we investigate the connection between Lyman continuum (LyC) escape and the conditions of the circumgalactic medium (CGM), as probed by Ly α halos (LAHs) in emission. We use Ly α and UV continuum imaging data from the Ly α and Continuum Origins Survey (LaCOS), targeting 42 nearby ( z ≃0.3), star-forming galaxies with LyC observations (escape fractions of f esc LyC ≃ 0.01 − 0.49 ). LaCOS galaxies show extended Ly α emission ubiquitously, with LyC emitters (LCEs) having more compact Ly α morphologies than non-LCEs, and Ly α spatial offsets…