Ly Emission from a Lyman Limit Absorber at z = 3 . 036 ?

Deep, 17.8 hours, narrow band imaging obtained at the ESO 3.5m New Technology Telescope has revealed extended (galaxy sized) Ly emission from a high redshift Lyman limit absorber. The absorber is a zabs zem Lyman limit absorber seen in the spectrum of Q1205-30 at zem=3.036. The Ly luminosity of the emission line object is 12–14 1041 h 2 erg s 1 for m=1. The size and morphology of the Ly 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., 1999a), suggesting a close connection between Lyman limit absorbers and DLAs. We also detect six candidate Ly emitting galaxies in the surrounding field at projected distances of 156–444h 1 kpc with Ly luminosities ranging from 3.3 to 9.5 1041 h 2 erg s 1 for m=1. Assuming no obscuration of Ly by dust this corresponds to star formation rates in the range 0.3 – 0.9 h 2 M yr 1. 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.