INFRARED EMISSION-LINE GALAXIES ASSOCIATED WITH DAMPED LY-ALPHA AND STRONG METAL ABSORBER REDSHIFTS

Eighteen candidates for emission-line galaxies were discovered in a na rrowband infrared survey that targeted the redshifts of damped Ly alph a or metal lines in the spectra of quasars. The presence of emission l ines is inferred from the photometric magnitudes in narrowband and bro adband interference filters, corresponding to H alpha at redshifts of 0.89 (six objects) and 2.4 (10 objects) and to [O II] lambda 3727 at a redshift of 2.3 (two objects). Most of the candidates are small, reso lved objects that are compatible with galaxies at the redshifts of the damped Ly alpha absorbers. Because a similar survey, targeted at the redshifts of quasars themselves, uncovered only one emission-line gala xy in a larger volume, the results imply substantial clustering of you ng galaxies or a formation within filaments or sheets whose locations are indicated by the redshifts of strong Ly alpha line absorption alon g the lines of sight to more distant quasars.