2025A&A...704A.328L

Identifying Lyman continuum (LyC) leakers at intermediate redshifts is crucial for understanding the properties of cosmic reionizers because the opacity of the intergalactic medium (IGM) prevents the direct detection of LyC emission from sources during the Epoch of Reionization (EoR). In this study, we confirm two new LyC candidate leakers at z ∼ 3 in the Abell 2744 cluster field, with absolute escape fractions (f_esc) of $ 0.83^{+0.15}_{-0.80} $ and $ 0.74^{+0.23}_{-0.70} $, respectively. The LyC emission was detected using HST/WFC3/F275W and F336W imaging. These two candidate leakers appear to be faint (M_UV = -17.61 ± 0.06 and -18.22 ± 0.10), exhibit blue UV continuum slopes (β = -2.43 ± 0.05 and -1.92 ± 0.09), have low masses (M_★ ∼ 10^7.51 ± 0.03^ and 10^7.17 ± 0.15^ M_⊙) and Lyα equivalent widths of 90 ± 3 Å and 28 ± 12 Å, respectively. These two LyC candidate leakers were detected in a catalog of 91 spectroscopically confirmed sources using public spectra from the JWST and/or MUSE. We also analyzed properties that were proposed as indirect indicators of LyC emission, such as Lyα, the O32 ratio, and M_★. We created a galaxy subsample that was selected according to these properties, stacked the LyC observations of this subsample, and assessed the limits of the escape fractions in the stacks. We aim to enhance our understanding of LyC escape mechanisms and improve our predictions of the LyC f_esc during the EoR by analyzing the individual candidates and the stacks in the context of the currently limited sample of known LyC leakers at z ∼ 3.