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A critical analysis of interstellar Zn and Cr as galactic abundance benchmarks for quasar absorbersWe present interstellar gas-phase abundances of zinc and chromium in the Milky Way for comparison with the abundances of these elements in damped Ly-alpha systems at redshifts near z approximately 2. We make use of both IUE (International Ultraviolet Explorer) and GHRS (Goddard High Resolution Spectrograph) archival information in deriving the Milky Way values and find that the average difference in (Zn/H) and (Cr/Zn) between the Milky Way and damped Ly-alpha systems at large N(H1) is about 0.9 dex. The Zn/H values we find for the Milky Way are approximately -0.2 to -0.7 dex below solar and are due in large part to depletion of Zn onto dust grains. The amount of this gas-phase depletion is variable and depends upon the H1 column density and molecular fraction of the gas. Milky Way sight lines having low molecular fractions have values of (Zn/H) within approximately 0.2 dex of the solar value. Combined with larger values of (Cr/Zn) found for the damped Ly-alpha systems, this result confirms that measures of (Zn/H) should accurately reflect the lower gas-phase abundances of Zn found in these systems.
Document ID
19950056277
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Sembach, Kenneth R.
(Massachusetts Institute of Technology, Cambridge, Massachusetts United States)
Steidel, Charles C.
(Massachusetts Institute of Technology, Cambridge, Massachusetts United States)
Macke, Robert J.
(Massachusetts Institute of Technology, Cambridge, Massachusetts United States)
Meyer, David M.
(Northwestern University Evanston, Illinois, United States)
Date Acquired
August 16, 2013
Publication Date
May 20, 1995
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 445
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A87876
Funding Number(s)
CONTRACT_GRANT: NAG5-2659
CONTRACT_GRANT: HF-1038.01-92A
Distribution Limits
Public
Copyright
Other

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