Identification of absorbing galaxies towards the QSO J2233-606 in the Hubble Deep Field South

Abstract

We present spectroscopic observations of galaxies lying within 1' of QSO J2233-606 in the Hubble Deep Field South (HDF-S). Several are found to be coincident in redshift with absorption-line systems seen in the HST J2233-606 spectrum. We detect a new z_em = 1.336 QSO with I = 20.8 at a projected angular separation of 44.5'' (or rho = 200h(-1) kpc; q_0 = 0.5) from J2233-606. This QSO pair is an ideal target for QSO environment studies. Indeed, strong H I Lyalpha and Lybeta absorptions are seen at z_abs = 1.3367 in the J2233-606 spectrum. The bright spiral galaxy (J2233378-603324), projected at 4.7'' from J2233-606, is at z = 0.570 (thus rho = 18h(-1) kpc). Absorption is seen in the Lyman series at the same redshift but the weakness of the Lyman break implies N(H I) < 10(17) cm(-2) . Based on observations obtained with the NTT at the European Southern Observatory, La Silla, Chile under programs 61.A-0631 and 62.O-0363; and with the NASA/ESA Hubble Space Telescope by the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.