The Column Density Distribution Function at z=0 from HI Selected Galaxies
| dc.creator | Ryan-Weber, Emma | |
| dc.creator | Webster, Rachel | |
| dc.creator | Staveley-Smith, Lister | |
| dc.date | 2003-05-01 | |
| dc.date.accessioned | 2026-07-07T10:47:37Z | |
| dc.date.available | 2026-07-07T10:47:37Z | |
| dc.description | We have measured the column density distribution function, f(N), at z=0 using 21-cm HI emission from galaxies selected from a blind HI survey. f(N) is found to be smaller and flatter at z=0 than indicated by high-redshift measurements of Damped Lyman-alpha (DLA) systems, consistent with the predictions of hierarchical galaxy formation. The derived DLA number density per unit redshift, dn/dz =0.058, is in moderate agreement with values calculated from low-redshift QSO absorption line studies. We use two different methods to determine the types of galaxies which contribute most to the DLA cross-section: comparing the power law slope of f(N) to theoretical predictions and analysing contributions to dn/dz. We find that comparison of the power law slope cannot rule out spiral discs as the dominant galaxy type responsible for DLA systems. Analysis of dn/dz however, is much more discriminating. We find that galaxies with log M_HI < 9.0 make up 34% of dn/dz; Irregular and Magellanic types contribute 25%; galaxies with surface brightness > 24 mag arcsec^{-2} account for 22% and sub-L* galaxies contribute 45% to dn/dz. We conclude that a large range of galaxy types give rise to DLA systems, not just large spiral galaxies as previously speculated. | |
| dc.description | 13 pages, low resolution figures in the appendix, MNRAS accepted | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0305010 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0305010 | |
| dc.identifier | Mon.Not.Roy.Astron.Soc.343:1195,2003; Erratum-ibid.356:1600,2005 | |
| dc.identifier | doi:10.1111/j.1365-2966.2004.08633.x/abs/ | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/183598 | |
| dc.subject | Astrophysics | |
| dc.title | The Column Density Distribution Function at z=0 from HI Selected Galaxies | |
| dc.type | text |