Early Results from GLASS-JWST XXIII: The transmission of Lyman-alpha from UV-faint z ~ 3-6 galaxies

Understand

Lyman-alpha (Ly$\alpha$) emission from galaxies can be used to trace neutral hydrogen in the epoch of reionization, however, there is a degeneracy between the attenuation of Ly$\alpha$ in the intergalactic medium (IGM) and the line profile emitted from the galaxy.

• Large shifts of Ly$\alpha$ redward of systemic due to scattering in the interstellar medium can boost Ly$\alpha$ transmission in the IGM during reionization.
• The relationship between Ly$\alpha$ velocity offset from systemic and other galaxy properties is not well-established at high-redshift or low luminosities, due to the difficulty of observing emission lines which trace systemic redshift.
• Rest-frame optical spectroscopy with JWST/NIRSpec has opened a new window into understanding of Ly$\alpha$ at z>3.