Damped Lyman-Alpha Absorption by Disk Galaxies with Large Redshifts. I. The Lick Survey

As a first step in a survey for remote galaxies, low-resolution (delta lambda = 10 angstroms) spectra of 68 high-redshift QSOs were obtained. The idea is to locate the large column density of neutral hydrogen in the disks of foreground galaxies through the detection of Ly-alpha absorption lines broadened by radiation damping. The damped lines are valuable signatures of high-r-redshift galaxies, since they are predicted to much stronger than Ly-alpha absorption lines typically found in the spectra of QSOs. A list of absorption features that are candidates for 'Ly-alpha disks'. The spectra of all 68 QSOs are presented as plots of flux vs wavelength along with the 1-sigma error in flux vs wavelength. The plots also designate absorption features that are located blueward of Ly-alpha emission and deemed to be significant by criteria that are given. Fifteen absorption features are seen to be damped Ly-alpha, and 10 are blends of multiple narrow components that are separated by Doppler velocities of about 1000 km/s. Preliminary evidence indicates that the damped lines and the multicomponent lines are drawn from distinct populations of absorbers.