2009MNRAS.393.1513M

The damped Lyman α (DLA) and sub-damped Lyman α (sub-DLA) systems seen in the spectra of quasi-stellar objects (QSOs) offer a unique way to study the interstellar medium (ISM) of high-redshift galaxies. In this paper, we report on new abundance determinations in a sample of 10 new systems, nine of the lesser studied sub-DLAs and one DLA along the line of sight to seven QSOs from spectra taken with the Magellan Inamori Kyocera Echelle spectrograph. Lines of Mgi, Mgii, Alii, Aliii, Caii, Mnii, Feii and Znii were detected. Here, we give the column densities and equivalent widths of the observed absorption lines, as well as the abundances determined for these systems. Zn, a relatively undepleted element in the local ISM is detected in one system with a high metallicity of [Zn/H] = +0.27±0.18. In another system, a high abundance based on the more depleted element Fe is seen with [Fe/H] = -0.37±0.13, although Zn is not detected. The -weighted mean metallicity of these sub-DLA systems based on Fe is <[Fe/H]> = -0.76±0.11, nearly ∼0.7 dex higher (a factor of 5) than what is seen in DLAs in this redshift range. The relative abundance of [Mn/Fe] is also investigated. A clear trend is visible for these systems as well as systems from the literature, with [Mn/Fe] increasing with increasing metallicity in good agreement with Milky Way stellar abundances.