The Sloan Digital Sky Survey Damped Lyα 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 data set has greater statistical significance than the previous two decades of research. We derive a statistical sample of 71 DLA 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50 previously unpublished) at z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 more than 95% completeness. We examine the cosmological baryonic mass density of neutral gas, Ω g , inferred from the DLA systems from the SDSS‐DR1 survey and a combined sample drawn from the literature. Contrary to previous results, the Ω g values do not require a significant correction from Lyman limit systems at any redshift. We also find that the Ω g 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 Ω g at higher redshift.