The Epoch of Reionization (EoR) began when galaxies grew in abundance and
luminosity, so their escaping Lyman continuum (LyC) radiation started ionizing
the surrounding neutral intergalactic medium (IGM). Despite significant recent
progress, the nature and role of cosmic reionizers are still unclear: in order
to define them, it would be necessary to directly measure their LyC escape
fraction (fesc). However, this is impossible during the EoR due to the
opacity of the IGM. Consequently, many efforts at low and intermediate redshift
have been made to determine measurable indirect indicators in high-redshift
galaxies so that their fesc can be predicted. This work presents the
analysis of the indirect indicators of 62 spectroscopically confirmed
star-forming galaxies at 6≤z≤9 from the Cosmic Evolution Early
Release Science (CEERS) survey, combined with 12 sources with public data from
other JWST-ERS campaigns. From the NIRCam and NIRSpec observations, we measured
their physical and spectroscopic properties. We discovered that on average
6<z<9 star-forming galaxies are compact in the rest-frame UV (re∼ 0.4
kpc), are blue sources (UV-β slope ∼ -2.17), and have a predicted
fesc of about 0.13.
A comparison of our results to models and predictions as well as an
estimation of the ionizing budget suggests that low-mass galaxies with UV
magnitudes fainter than M1500=−18 that we currently do not characterize
with JWST observations probably played a key role in the process of
reionization.Comment: 14 pages, 11 figures, submitted to A&