Open AccessElemental abundance measurements in low‐redshift damped Lyman α absorbers
Author(s) -
Meiring Joseph D.,
Kulkarni Varsha P.,
Khare Pushpa,
Bechtold Jill,
York Donald G.,
Cui Jun,
Lauroesch James T.,
Crotts Arlin P. S.,
Nakamura Osamu
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10500.x
Subject(s) - metallicity , physics , astrophysics , redshift , metal , abundance (ecology) , cosmic cancer database , spectral line , astronomy , galaxy , chemistry , organic chemistry , fishery , biology
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 H i 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 H i ‐weighted mean metallicity versus redshift for our sample combined with data from the literature supports previous conclusions that the N H i ‐weighted mean global DLA metallicity rises slowly at best and falls short of solar levels by a factor of >4 even at z = 0.