2000A&A...353..457F

Deep, 17.8 hours, narrow band imaging obtained at the ESO 3.5m New Technology Telescope has revealed extended (galaxy sized) Lyα emission from a high redshift Lyman limit absorber. The absorber is a z_abs≃z_em Lyman limit absorber seen in the spectrum of Q1205-30 at z_em=3.036. The Lyα luminosity of the emission line object is 12-14x10⁴¹h^–2.erg/s for Ω_m=1. The size and morphology of the Lyα emitter are both near-identical to those of a previously reported emission line object associated with a DLA at z=1.934 (Fynbo et al., 1999MNRAS.305..849F), suggesting a close connection between Lyman limit absorbers and DLAs. We also detect six candidate Lyα emitting galaxies in the surrounding field at projected distances of 156-444h^–1kpc with Lyα luminosities ranging from 3.3 to 9.5x10⁴¹h^–2erg/s for Ω_m=1. Assuming no obscuration of Lyα by dust this corresponds to star formation rates in the range 0.3-0.9h^–2M_☉/yr. Comparing this to the known population of high redshift Lyman break galaxies, we find that the Lyman break galaxies in current ground based samples only make up the very bright end of the high redshift galaxy luminosity function. A significant, and possibly dominating, population of high redshift galaxies are not found in the ground based Lyman break surveys.