Challenging the LyC-Ly relation: strong Ly emitters without LyC leakage at z 2. 3

The escape fraction of LyC ionizing radiation f₋ₘ₂^esc is crucial for understanding reionization, yet impossible to measure at z 5. 3. Recently, studies have focused on calibrating indirect indicators of f₋ₘ₂^esc at z 0. 3, finding that Ly is closely linked to it. What is still unclear is whether the LyC - Ly relation evolves with redshift, and if Ly is truly applicable as an f₋ₘ₂^esc indicator during the reionization epoch. In this study, we investigate seven -21 Mₔₕ -19 gravitationally lensed galaxies from the BELLS GALLERY survey at z 2. 3. Our targets have rest-frame Ly equivalent widths ranging from 10 A to 100 A and low dust content (-2. 5 -1. 9), both indicative of high LyC escape. Surprisingly, direct estimates of f₋ₘ₂^esc using Hubble Space Telescope imaging with F275W and F225W reveal that our targets are not LyC emitters, with absolute f₋ₘ₂^esc 6. 5% at 3 significance (with two sources having absolute f₋ₘ₂^esc (3) 10% and 16%). The low f₋ₘ₂^esc, coupled with the high Ly escape fraction and equivalent width could potentially be attributed to the redshift evolution of the neutral hydrogen column density and dust content. Our results challenge previous studies based on local samples, suggesting that the extrapolation of z ~ 0 Ly-based LyC indirect estimators into the reionization epoch might not be correct.