The ISM properties of Lyman Continuum Emitters

The contribution of star-forming galaxies to Reionization is still unknown. Using 66 ultraviolet (UV) spectra from the recent Low-Redshift Lyman Continuum Survey (LzLCS) and 23 archival Lyman Continuum (LyC) observations, we form a statistical sample of compact star forming galaxies at z = 0.2 - 0.4 to study the role of the cool Interstellar Medium gas (ISM gas, traced by the UV absorption lines) in the leakage of ionizing radiation (LyC escape fraction, fesc). Strong LyC leakers (high fesc) show weak absorption lines, low UV attenuation, and large Lyman Alpha equivalent widths. The observed non-uniform gas coverage (non-zero residual flux of the UV lines) demonstrates that LyC photons escape through low-column-density channels in a patchy/clumpy ISM. Finally, we show that simultaneous measurement of UV absorption lines and dust attenuation can statistically predict the absolute LyC escape fraction of galaxies, and the method can be applied to study galaxies across a wide redshift range.