2024ApJ...972...92J

To understand how galaxies reionized the Universe, we must determine how the escape fraction of Lyman continuum (LyC) photons (f_esc) depends on galaxy properties. Using the z ∼ 0.3 Low-redshift Lyman Continuum Survey (LzLCS), we develop and analyze new multivariate predictors of f_esc. These predictions use the Cox proportional hazards model, a survival analysis technique that incorporates both detections and upper limits. Our best model predicts the LzLCS f_esc detections with an rms scatter of 0.31 dex, better than single-variable correlations. According to ranking techniques, the most important predictors of f_esc are the equivalent width (EW) of Lyman-series absorption lines and the UV dust attenuation, which track line-of-sight absorption due to H I and dust. The H I absorption EW is uniquely crucial for predicting f_esc for the strongest LyC emitters, which show properties similar to weaker LyC emitters and whose high f_esc may therefore result from favorable orientation. In the absence of H I information, star formation rate surface density (Σ_SFR) and [O III]/[O II] ratio are the most predictive variables and highlight the connection between feedback and f_esc. We generate a model suitable for z > 6, which uses only the UV slope, Σ_SFR, and [O III]/[O II]. We find that Σ_SFR is more important in predicting f_esc at higher stellar masses, whereas [O III]/[O II] plays a greater role at lower masses. We also analyze predictions for other parameters, such as the ionizing-to-nonionizing flux ratio and Lyα escape fraction. These multivariate models represent a promising tool for predicting f_esc at high redshift.