Physical origin of scatter in Lyα escape at z ≈ 6

Determine what drives the scatter in the Lyα escape fraction of star-forming galaxies at z ≈ 6 and quantify how much of the observed variation is caused by intrinsic interstellar-medium conditions rather than intergalactic-medium transmission.

Background

The paper emphasizes that Lyα visibility at z ≈ 6 is influenced by both galaxy-scale processes and attenuation in the surrounding intergalactic medium. Existing evidence implicates neutral-hydrogen column density, dust content, gas geometry, gas kinematics, ionizing-photon production efficiency, and stellar-population metallicity, but their relative contributions remain unresolved. Establishing the origin of the observed scatter is important for interpreting Lyα suppression at higher redshift, where intergalactic-medium attenuation becomes increasingly significant.

References

As a result, it remains unclear what drives the scatter in $f_\mathrm{esc}\mathrm{Ly\alpha}$ at this epoch, and how much of the observed variation reflects intrinsic ISM conditions rather than IGM transmission.

— Constraining reionization-era Ly$α$ escape with JELS-MUSE: a highly complete H$α$-selected sample at $z\sim6.1$  (2609.02558 - Patrick et al., 2 Sep 2026) in Section 1, Introduction