Ly-alpha Emission from a Lyman Limit Absorber at z=3.036

Research paper by J. U. Fynbo, B. Thomsen, P. Moller

Indexed on: 09 Nov '99Published on: 09 Nov '99Published in: Astrophysics


Deep, 17.8 hours, narrow band imaging obtained at the ESO 3.5m New Technology Telescope has revealed extended (galaxy sized) Ly-alpha emission from a high redshift Lyman limit absorber. The absorber is a z(abs) approx. z(em) Lyman limit absorber seen in the spectrum of Q1205-30 at z(em)=3.036. The Ly-alpha luminosity of the emission line object is 12-14 x 10e41 h^-2 erg/s for Omega(matter)=1. The size and morphology of the Ly-alpha 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-alpha emitting galaxies in the surrounding field at projected distances of 156-444 h^-1 kpc with Ly-alpha luminosities ranging from 3.3 to 9.5 x 10e41 h^-2 erg/s for Omega(matter)=1. Assuming no obscuration of Ly-alpha photons by dust this corresponds to star formation rates in the range 0.3-0.9 h^-2 M(sun)/yr. Comparing this to the 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.