The Damping Wing of the Gunn-Peterson Absorption and Lyα Emitters in the Pre-Reionization Era

We use a numerical simulation of cosmological reionization to estimate the likelihood of detecting Lyα-emitting galaxies during the pre-reionization era. We show that it is possible to find galaxies even at z ~ 9 that are barely affected by the damping wing of the Gunn-Peterson absorption from the neutral intergalactic medium outside of their H II regions. The damping wing becomes rapidly more significant at z > 9, but even at z > 10 is it not inconceivable (although quite hard) to see a Lyα emission line from a star-forming galaxy.