Metal abundances at z < 1.5:: new measurements in sub-damped Lyman α absorbers

Damped Lyman alpha systems (DLAs) and sub-DLAs seen towards background quasars provide the most detailed probes of elemental abundances. Somewhat paradoxically these measurements are more difficult at lower redshifts due to the atmospheric cut-off, and so a few years ago our group began a program to study abundances at z < 1.5 in quasar absorbers. In this paper, we present new Ultraviolet and Visual Echelle Spectrograph (UVES) observations of six additional quasar absorption-line systems at z < 1.5, five of which are sub-DLAs. We find solar or above solar metallicity, as measured by the abundance of zinc, assumed not to be affected by dust, in two sub-DLAs: one, towards Q0138-0005 with [Zn/H] = +0.28 +/- 0.16 ; the other towards Q2335+1501 with [Zn/H] = +0.07 +/- 0.34 . Relatively high metallicity was observed in another system: Q0123-0058 with [Zn/H] = -0.45 +/- 0.20 . Only for the one DLA in our sample, in Q0449-1645, do we find a low metallicity, [Zn/H] = -0.96 +/- 0.08 . We also note that in some of these systems large relative abundance variations from component to component are observed in Si, Mn, Cr and Zn.