Metals and Dust in Intermediate-redshift Damped Ly-alpha Galaxies
Abstract
We report spectroscopic observations with the Multiple Mirror Telescope for 11 damped Lyman-alpha absorbers (DLAs) or strong DLA candidates at 0.1 < z < 1.5, including several absorbers discovered in the Sloan Digital Sky Survey. In particular, we have measured absorption lines of Zn II, Cr II, Ni II, Fe II, Mn II, Ti II, Ca II, and Si II. These measurements have doubled the sample of Zn and Cr measurements at z < 1. The average relative abundance patterns in these objects are very similar to those found for high-redshift DLAs reported in the literature. Our observations suggest that the dust content, as determined by [Cr/Zn], does not show much change with redshift. We also examine the sample for correlation of [Cr/Zn] with estimates of the quasar reddening. Our data suggest that the global mean metallicity of DLAs, as measured by the gas phase abundance of Zn, at best shows a weak evolution with redshift over the range 0.4 < z <3.9.
Keywords
Cite
@article{arxiv.astro-ph/0408139,
title = {Metals and Dust in Intermediate-redshift Damped Ly-alpha Galaxies},
author = {Pushpa Khare and Varsha P. Kulkarni and James T. Lauroesch and Donald G. York and Arlin P. S. Crotts and Osamu Nakamura},
journal= {arXiv preprint arXiv:astro-ph/0408139},
year = {2009}
}
Comments
aastex52, 47 pages including 11 postscript figures. Accepted for publication in The Astrophysical Journal