NICMOS Snapshot Survey of Damped Lyα Quasars

摘要

We image 19 quasars with 22 damped Lyα systems (DLAs) using the F160W filter and the Near-Infrared Camera and Multi-Object Spectrograph on board the Hubble Space Telescope in both direct and coronagraphic modes. We reach 5 σ detection limits of ~H = 22 in the majority of our images. We compare our observations to the observed Lyman break population of high-redshift galaxies as well as Bruzual & Charlot evolutionary models of present-day galaxies redshifted to the distances of the absorption systems. We predict H magnitudes for our DLAs, assuming that they are producing stars like an L* Lyman break galaxy (LBG) at their redshift. Comparing these predictions to our sensitivity, we find that we should be able to detect a galaxy around 0.5-1.0 L*(LBG) for most of our observations. We find only one new possible candidate, that near LBQS 0010-0012. This scarcity of candidates leads us to the conclusion that most damped Lyα systems are not drawn from a normal LBG luminosity function nor a local galaxy luminosity function placed at these high redshifts.