Models for high-redshift Lyα emitters

We present models for dusty high–redshift Lyα emitting galaxies by combining the Press–Schechter formalism with a treatment of inhomogeneous dust distribution inside galaxies. These models reproduce the surface density of emitters inferred from recent observations, and also agree with previous non–detections. Although a detailed determination of the individual model parameters is precluded by uncertainties, we find that (i) the dust content of primordial galaxies builds up in no more than ∼ 5 × 10^8 yr, (ii) the galactic HII regions are nhomogeneous with a cloud covering factor of order unity, and (iii) the overall star formation efficiency is at least ∼ 5%. Future observations should be able to detect Lyα galaxies upto redshifts of z ∼ 8. If the universe is reionized at zr ∼< 8, the corresponding decline in the number of Lyα emitters at z ∼> zr could prove to be a useful probe of the reionization epoch.