Samenvatting
Blind 21cm surveys in the local universe have shown that the local HI
mass density, Omega_HI, is dominated by luminous, high surface
brightness, spiral galaxies. On the other hand, surveys for host
galaxies of damped Ly-alpha (DLA) systems have not always been
successful in finding bright spiral galaxies. From an analysis of 21cm
aperture synthesis maps of nearby galaxies we show that this apparent
contradiction can be resolved by realizing that the HI mass density is
dominated by L* galaxies, but the HI cross-section near the DLA
threshold is more evenly distributed over galaxies with a large range in
luminosity, gas mass, and surface brightness. The distributions of
column densities and impact parameters of optically identified and
non-identified DLA host galaxies in the literature and the HI maps are
qualitatively in agreement. Due to poor number statistics of low
redshift DLA systems, there is no firm indication that the redshift
number count of low redshift DLA systems is inconsistent with that
calculated from the nearby galaxy population.
Originele taal-2 | English |
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Pagina's | 169 |
Status | Published - 2002 |
Evenement | Extragalactic Gas at Low Redshift, ASP Conference Proceedings - San Francisco, United States Duur: 1-jan.-1970 → … |
Conference
Conference | Extragalactic Gas at Low Redshift, ASP Conference Proceedings |
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Land/Regio | United States |
Stad | San Francisco |
Periode | 01/01/1970 → … |