Reionization morphology and intrinsic velocity offsets allow transmission of Lyman-{\alpha} emission from JADES-GS-z13-1-LA

TL;DR

This study models the conditions under which Lyman-alpha emission from galaxies at the epoch of reionization can be detected, emphasizing the impact of reionization morphology and galaxy properties on observability.

Contribution

It combines galaxy formation models with IGM reionization simulations to assess Ly$ extalpha$ detectability at $z=13$, highlighting the role of reionization morphology.

Findings

Ly$ extalpha$ transmission for a $M_{UV} extasciitilde -18.5$ galaxy is about 13%.

Detection probability of Ly$ extalpha$ emission can reach up to 10-12% depending on reionization models.

Reionization driven by low-mass galaxies enhances Ly$ extalpha$ detectability.

Abstract

We investigate the detectability of Lyman-$\alpha$ (Ly$\alpha$) emission from galaxies at the onset of cosmic reionization, aiming to understand the conditions necessary for detecting high-redshift sources like JADES-GS-z13-1-LA at $z=13$. By integrating galaxy formation models with detailed intergalactic medium (IGM) reionization simulations, we construct high-redshift galaxy catalogs to model intrinsic Ly$\alpha$ profiles and assess their transmission through the IGM. For a galaxy with $M_{\rm UV}\sim -18.5$ like JADES-GS-z13-1-LA, our fiducial model predicts a Ly$\alpha$ transmission of ${\sim}13$% and there is a probability of observing Ly$\alpha$ emission with an equivalent width >40A of up to 10%. We also explore how variations in the UV ionizing escape fraction, dependent on host halo mass, impact Ly$\alpha$ detectability. Our findings reveal that reionization morphology significantly influences detection chances -- models where reionization is driven by low-mass galaxies can boost the detection probability to as much as 12%, while those driven by massive galaxies tend to reduce ionized regions around faint emitters, limiting their detectability. This study underscores the importance of reionization morphology in interpreting high-redshift Ly$\alpha$ observations.