Adaptive Optics Imaging of Low-Redshift Damped Lyα Quasar Absorbers

Abstract

We have carried out a high angular resolution near-infrared imaging study of the fields of six quasars with seven strong absorption-line systems at z<0.5, using the Hokupa'a adaptive optics system and the Quick Infrared Camera on the Gemini North telescope. These absorption systems include four classical damped Lyα absorbers (DLAs), two sub-DLAs, and one Lyman limit system. Images were obtained in the H or K' filters with FWHM between 0.2" and 0.5" with the goal of detecting the absorbing galaxies and identifying their morphologies. Features are seen at projected separations of 0.5"-16.0" from the quasars, and all the fields show features at less than 2" separation. We find candidate absorbers in all seven systems. With the assumption that some of these are associated with the absorbers, the absorbers are low-luminosity <=0.1L^*_H or L^*_K; we do not find any large, bright candidate absorbers in any of our fields. Some fields show compact features that are too faint for quantitative morphology but could arise in dwarf galaxies.