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1996PASP..108..641L - Publ. Astron. Soc. Pac., 108, 641-658 (1996/August-0)
QSO absorption line systems and early chemical evolution.
LAUROESCH J.T., TRURAN J.W., WELTY D.E. and YORK D.G.
Abstract (from CDS):
The range of overall abundances (10^-0.5 to 10^-3 solar) found in the absorbers (at redshifts of 0.6-3.4) overlaps the range found in Galactic halo stars. Specific, measurable tracers of supernova activity and dust grain formation in the absorber population are identified. As yet, however, there is no evidence of a system with [O/Zn]> 0 , [S/Zn]> 0, or [Si/Zn]> 0, the most distinguishing characteristic of Galactic halo star abundances. Dust-free gas with halo star abundances and solar metallicity gas with a Galactic cold-cloud depletion pattern are excluded by existing data.
Additional observations of absorption line systems with 10^19 < N(H I) < 10^22 to obtain abundances of Al, Si, S, Mn, Fe, and Zn are needed. High spectral resolution is critical so that H I and H II regions may be identified and separated; otherwise the derived abundances are only upper limits. Future observations of O, N, Ca, Ti and Cr should shed new light on the origin of the elements and of grains in the absorbers. Observed cosmic timescales for elemental buildup can lead to specific predictions for the typical rates of Type I and Type II SNe as a function of redshift.
Abstract Copyright: ∼
Journal keyword(s): Invited Review
CDS comments: QSO 0215+215 misprint for 0215+025, QSO 1230+025 not identified
Simbad objects: 25
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