Speaker
Description
Constraining the Lyman continuum (LyC) escape fraction, fesc, at high redshifts is essential for mapping the ionizing emissivity of early galaxies during Reionization, but attenuation by the neutral IGM renders direct measurements impossible. As such, various diagnostics, such as [OIII]/[OII] ratios, UV-slope, etc., have been studied in local high-redshift analogs to develop techniques to infer fesc. While no single diagnostic has prevailed as a feasible model to constrain fesc at high-z, the consensus of these studies concludes that line of sight (LOS) diagnostics are essential for measuring fesc. Understanding the relationship between galaxy properties and the LOS geometry of neutral gas and dust content of the ISM/CGM is therefore paramount to understanding the physics which reionized the universe. In this talk, we present on our work to study the influence of cool outflows on LyC escape in a sample of confirmed LyC leakers and non-leakers taken from the low-z LyC survey (LzLCS). Specifically, we perform radiation transfer modeling of the Mg II 2796A, 2803A doublet in high resolution follow-up spectra of the LzLCS galaxies to map the cool phase of their outflows. Assuming Mg+ traces neutral hydrogen, we infer the neutral hydrogen distribution to predict fesc with cloudy models. Our predictions often overestimate fesc, suggesting that moderately optically thin gas significantly influences fesc in addition to the binary optically thick and thin LOS distributions typically assumed in these types of models. Lastly, we present on our results pertaining to how outflow properties, such as mass outflow rate and velocity dispersion, impact fesc in the compact + high star formation rate surface density regime, where the strongest LyC emitters lie in LzLCS.
