The Great Escape: Understanding the connection between Lyα emission and LyC escape in simulated JWST Analogues
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 532:2 (2024) stae1586
Authors:
Nicholas Choustikov, Harley Katz, Aayush Saxena, Thibault Garel, Julien Devriendt, Adrianne Slyz, Taysun Kimm, Jeremy Blaizot, Joki Rosdahl
Abstract:
Constraining the escape fraction of Lyman Continuum (LyC) photons from high-redshift galaxies is crucial to understanding reionization. Recent observations have demonstrated that various characteristics of the Ly emission line correlate with the inferred LyC escape fraction () of low-redshift galaxies. Using a data set of 9600 mock Ly spectra of star-forming galaxies at from the SPHINX cosmological radiation hydrodynamical simulation, we study the physics controlling the escape of Ly and LyC photons. We find that our mock Ly observations are representative of high-redshift observations and that typical observational methods tend to overpredict the Ly escape fraction () by as much as 2 dex. We investigate the correlations between and, Ly equivalent width (), peak separation (), central escape fraction (), and red peak asymmetry (). We find that and are good diagnostics for LyC leakage, selecting for galaxies with lower neutral gas densities and less UV attenuation that have recently experienced supernova feedback. In contrast, and are found to be necessary but insufficient diagnostics, while carries little information. Finally, we use stacks of Ly, H, and F150W mock surface brightness profiles to find that galaxies with high tend to have less extended Ly and F150W haloes but larger H haloes than their non-leaking counterparts. This confirms that Ly spectral profiles and surface brightness morphology can be used to better understand the escape of LyC photons from galaxies during the epoch of reionization.
