THE SDSS DAMPED Ly α SURVEY : DATA RELEASE 1

We present the results from an automated search for damped Lyα (DLA) systems in the quasar spectra of Data Release 1 from the Sloan Digital Sky Survey (SDSS-DR1). At z ≈ 2.5, this homogeneous dataset has greater statistical significance than the previous two decades of research. We derive a statistical sample of 71 damped Lyα systems (> 50 previously unpublished) at z > 2.1 and measure H I column densities directly from the SDSS spectra. The number of DLA systems per unit redshift is consistent with previous measurements and we expect our survey has > 95% completeness. We examine the cosmological baryonic mass density of neutral gas Ωg inferred from the damped Lyα systems from the SDSS-DR1 survey and a combined sample drawn from the literature. Contrary to previous results, the Ωg values do not require a significant correction from Lyman limit systems at any redshift. We also find that the Ωg values for the SDSS-DR1 sample do not decline at high redshift and the combined sample shows a (statistically insignificant) decrease only at z > 4. Future data releases from SDSS will provide the definitive survey of DLA systems at z ≈ 2.5 and will significantly reduce the uncertainty in Ωg at higher redshift. Subject headings: Galaxies: Evolution, Galaxies: Intergalactic Medium, Galaxies: Quasars: Absorption Lines