2025ApJ...993..194N

Making use of JWST NIRSpec and NIRCam data, we conduct a detailed analysis of GN-z8-LAE, a strong Lyα emitter at z = 8.279. We investigate the interstellar medium (ISM) conditions that enable the Lyα detection in this source at the Epoch of Reionization (EoR) and scrutinize GN-z8-LAE as an early reionizer. In agreement with previous results, we find that GN-z8-LAE is a young galaxy (age ∼10 Myr) with a lower stellar mass (M^⋆ ∼ 10^7.66M_⊙) than most Lyα emitters (LAEs) at similar redshifts. The derived stellar-mass and star formation rate surface densities are ${\Sigma }_{{M}^{\star }}\sim 355\,{M}_{\odot }\,{\mathrm{pc}}^{-2}$ and Σ_SFR ∼ 88 M_⊙ yr^–1 kpc², respectively. Our spectral analysis indicates that: the Lyα line peak has a small velocity offset Δv = 133 ± 72 km s^–1 with respect to the galaxy systemic redshift; C IV]/C III] ≈ 3.3; and the ISM is characterized by a hard ionization field, although no signatures of active galactic nuclei are present. Moreover, we report the presence of N III]λ1750 emission, implying supersolar N abundance, which makes GN-z8-LAE one of the first strong Lyα and nitrogen emitters at the EoR. Based on all these properties, we apply a wide range of methods to constrain the Lyman continuum escape fraction (${f}_{\mathrm{esc}}^{\mathrm{LyC}}$) of GN-z8-LAE and report ${f}_{\mathrm{esc}}^{\mathrm{LyC}}\gt 14 \% $ in all cases. Therefore, we conclude that GN-z8-LAE is a robust candidate for a Lyman continuum leaker at the EoR that is being caught at the moment of efficiently reionizing its surrounding medium.