Description
Lyman Continuum (LyC) escape is a fundamental parameter for understanding the evolution of galaxies and the intergalactic medium (IGM). To shed light on the connection between LyC escape, stellar population properties, and morphology, we investigate the escape fraction (𝑓esc) of LyC photons. Direct observation of LyC at the Epoch of Reionisation (z≳6) is impeded by absorption, necessitating indirect methods for inference. To test these methods, we examine low-redshift galaxies whose properties serve as suitable analogues for the high-redshift galaxies of interest. We utilise our Bayesian spectral energy distribution (SED) fitting code, PROSPECTOR, which incorporates a flexible star formation history, variable dust attenuation, a self-consistent model of nebular emission, and accounts for slit-loss effects. This enables simultaneous fitting of emission line fluxes and broadband photometry.
We analyse 66 known LyC emitters from the Low-redshift Lyman Continuum Survey (LzLCS) within multiple distinct modeling frameworks, exploring the influence of different priors of star formation histories and 𝑓esc as well as the inclusion and exclusion of slit-loss effects. We compare our results with those obtained through equivalent widths of nebular emission lines, emission line flux ratios, Ly𝛼 emission line profiles, SFR surface density, and UV continuum slope and magnitude. We discuss the various degeneracies affecting escape fraction estimations and critically evaluate the widely accepted results and methodologies used to infer escape fractions at high redshift.
Building on these results, we establish a stable modeling framework, which we apply to a mass-complete NIRSpec sample
of galaxies at the Epoch of Reionisation.
