THE NATURE OF DISTANT GALAXIES PRODUCING MULTIPLE C-IV ABSORPTION-LINES IN THE SPECTRA OF HIGH-REDSHIFT QUASARS

We demonstrate that deep infrared imagery is capable of detecting luminous L* galaxies to redshifts z similar or equal to 2 and that an appropriate search strategy for distant sources is to image QSOs whose spectra reveal multiple C IV absorption lines at intermediate redshifts, Z(abs) not equal z(em). Most of these systems have associated Mg II absorption. Using UKIRT's InSb IRCAM array, we have surveyed the fields of 11 QSOs to limits of K similar or equal to 20.3. A statistically significant excess of faint sources is found close to the QSO sight line. We discuss the possibility that this excess arises from sources physically associated with the QSO or lower redshift Mg II absorbers, but comparisons with earlier studies suggest the most likely explanation is that we have detected the multiple C IV absorbers and their associated galaxies. Most of the excess has a projected separation of only 30-40 kpc (H-0 = 50, q(0) = 0.5) if placed at the absorber redshift, implying a C IV impact parameter comparable to that found for Mg II systems at lower redshifts. This is consistent with the similarity between strong multiple C IV and strong Mg II absorption selected samples. At [z(abs)] similar or equal to 1.6, the K-band luminosities of our candidate absorbing population are similar to those of luminous galaxies today but the implied number density is higher than can be accounted for straightforwardly unless strong selection effects operate.