Open AccessMetallicity in damped Lyman‐ α systems: evolution or bias?
Author(s) -
Prantzos N.,
Boissier S.
Publication year - 2000
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 - 10.1046/j.1365-8711.2000.03382.x
Subject(s) - metallicity , physics , astrophysics , galaxy , chemical evolution , redshift , cosmic cancer database , quasar , galaxy formation and evolution , physical cosmology , astronomy , cosmology , dark energy
Assuming that damped Lyman‐ α (DLA) systems are galactic discs, we calculate the corresponding evolution of metal abundances. We use detailed multizone models of galactic chemical evolution (reproducing successfully the observed properties of disc galaxies) and appropriate statistics (including geometrical probability factors) to calculate the average metallicity as a function of redshift. The results are compatible with available observations, provided that observational biases are taken into account , as suggested by Boissé et al. In particular, high column density and high‐metallicity systems are not detected because the light of backround quasars is severely extinguished, while low column density and low‐metallicity systems are not detectable through their absorption lines by current surveys. We show that these observational constraints lead to a ‘no‐evolution’ picture for the DLA metallicity, which does not allow us to draw strong conclusions about the nature of those systems or about their role in ‘cosmic chemical evolution’.