On the Metallicities and Kinematics of the Circumgalactic Media of Damped Lya Systems at z 2.5

We use medium- and high-resolution spectroscopy of close pairs of quasars to analyze the circumgalactic medium (CGM) surrounding 32 damped Ly alpha absorption systems (DLAs). The primary quasar sightline in each pair probes an intervening DLA in the redshift range 1.6 < z(abs) < 3.5, such that the secondary sightline probes absorption from Ly alpha and a large suite of metal-line transitions (including O I, C II, C IV, Si II, and Si IV) in the DLA host galaxy's CGM at transverse distances 24 kpc <= R-perpendicular to <= 284 kpc. Analysis of Ly alpha in the CGM sightlines shows an anticorrelation between R-perpendicular to and H I column density (N-HI) with 99.8% confidence, similar to that observed around luminous galaxies. The incidences of C II and Si II with N > 10(13) cm(-2) within 100 kpc of DLAs are larger by 2 sigma than those measured in the CGM of Lyman break galaxies (C-f(N-CII) > 0.89 and C-f(NSiII) = 0.75(-0.17)(+0.12) Metallicity constraints derived from ionic ratios for nine CGM systems with negligible ionization corrections and N-HI > 10(18.5) cm(-2) show a significant degree of scatter (with metallicities/limits across the range -2.06 less than or similar to log Z/Z(circle dot) less than or similar to -0.75), suggesting inhomogeneity in the metal distribution in these environments. Velocity widths of C IV.1548 and low-ionization metal species in the DLA versus CGM sightlines are strongly (>2 sigma) correlated, suggesting that they trace the potential well of the host halo over R-perpendicular to less than or similar to 300 kpc scales. At the same time, velocity centroids for C IV lambda 1548 differ in DLA versus CGM sightlines by >100 km s(-1) for similar to 50% of velocity components, but few components have velocities that would exceed the escape velocity assuming dark matter host halos of >= 10(12)M(circle dot).