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On the Origin of Metallicity in Lyman-Alpha Forest Systems

Published online by Cambridge University Press:  19 July 2016

M. Chiba  and
B. B. Nath
M. Chiba
Affiliation:
National Astronomical Observatory, Mitaka, Tokyo 181, JAPAN
B. B. Nath
Affiliation:
Raman Research Institute, Bangalore-560080, INDIA

Extract

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Several recent observations indicate that even the low H I column density Lyα absorption lines may not be primordial, as they were previously thought to be. High-resolution observations using the Keck telescope (Cowie et al. 1995; Tytler et al 1995.; Songaila & Cowie 1996) have revealed that a large fraction of Lyα absorption lines with H I column density as low as NHI ~ 1014 cm−2 at redshift z ~ 3 are associated with metal lines (C IV). This fraction, hereafter denoted as fm, is estimated as 0.5-0.75. On the other hand, there is an indication that at low z a large fraction of Lyα absorption lines are directly associated with halos of visible galaxies. This fraction is hereafter denoted as fg. Lanzetta et al. (1995, hereafter LBTW) claimed fg ~ 0.6 at z ≲ 1 (see also Bowen, Pettini & Boyle 1997).

Type
Conference Papers in order of Presentation
Information
Symposium - International Astronomical Union , Volume 187: Cosmic Chemical Evolution , 2002 , pp. 123 - 127
Copyright
Copyright © 2002 

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