Elemental abundance measurements in low-redshift damped Lyman α absorbers

ABSTRACT We present elemental abundance measurements for 9 damped Ly-α systems (DLAs) and 1sub-DLA at 0.1.z .1.5 from recent observations with the Multiple Mirror Telescope. Mostof these absorbers are found to be metal-poor, while 2 are found to have ≈ 30 − 50% solarmetallicities. Combining our data with other data from the literature, we find that the systemswith higher [Zn/H] also have stronger depletion as measured by [Cr/Zn] and [Fe/Zn]. The re-lationship between the metallicity and H I column density is also investigated. Together withour previous MMT survey (Khare et al. 2004) we have discovered 2 of the 4 known absorbersat z < 1.5 that lie above (although near) the “obscuration threshold” . This appears to be aresult of selecting absorbers with strong metal lines in our sample. It would be interesting tofind other similar systems by observing a larger sample and st udy how much such systemscontribute to the cosmic budget of metals. Finally, an analysis of the N HI -weighted meanmetallicity vs. redshift for our sample combined with data from the literature supports previ-ous conclusions that the N