Elemental abundance measurements in low-redshift damped Lyman α absorbers

Joseph D. Meiring, Varsha P. Kulkarni, Pushpa Khare, Jill Bechtold, Donald G. York, Jun Cui, James T. Lauroesch, Arlin P.S. Crotts, Osamu Nakamura

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

We present elemental abundance measurements for nine damped Lyman α (Lyα) systems (DLAs) and one sub-DLA at 0.1 ≤ z ≤ 1.5 from recent observations with the Multiple Mirror Telescope (MMT). Most of these absorbers are found to be metal poor, while two are found to have ≈30-50 per cent solar metallicities. Combining our data with other data from the literature, we find that the systems with higher [Zn/H] also have stronger depletion as measured by [Cr/Zn] and [Fe/Zn]. The relationship between the metallicity and Hi column density is also investigated. Together with our previous MMT survey, we have discovered two of the four known absorbers at z < 1.5 that lie above (although near) the 'obscuration threshold'. This appears to be a result of selecting absorbers with strong metal lines in our sample. It would be interesting to find other similar systems by observing a larger sample and study how much such systems contribute to the cosmic budget of metals. Finally, an analysis of the N HI-weighted mean metallicity versus redshift for our sample combined with data from the literature supports previous conclusions that the N HI-weighted mean global DLA metallicity rises slowly at best and falls short of solar levels by a factor of >4 even at z = 0.

Original languageEnglish (US)
Pages (from-to)43-62
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Volume370
Issue number1
DOIs
StatePublished - Jul 2006

Keywords

  • Dust, extinction
  • Ism: abundances
  • Quasars: absorption lines

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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