Dark-ages Reionization and Galaxy Formation Simulation XX. The Ly$\alpha$ IGM transmission properties and environment of bright galaxies during the Epoch of Reionization

Understand

The highly neutral inter-galactic medium (IGM) during the Epoch of Reionization (EoR) is expected to suppress Ly$\alpha$ emission with damping-wing absorption, causing nearly no Ly$\alpha$ detection from star-forming galaxies at $z{\sim}8$.

• However, spectroscopic observations of the 4 brightest galaxies (${\rm H}_{160}{\sim}25$ mag) at these redshifts do reveal prominent Ly$\alpha$ line, suggesting locally ionised IGM.
• In this paper, we explore the Ly$\alpha$ IGM transmission and environment of bright galaxies during the EoR using the Meraxes semi-analytic model.
• We find brighter galaxies to be less affected by damping-wing absorption as they are effective at ionizing surrounding neutral hydrogen.