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Date and Time of the Query: 2019-07-17 T11:38:01 PDT
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For refcode 2003MNRAS.343.1195R:
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Copyright by Royal Astronomical Society. 2003MNRAS.343.1195R The column density distribution function at z= 0 from HI selected galaxies Ryan-Weber, Emma V.; Webster, Rachel L.; Staveley-Smith, Lister Abstract. We have measured the column density distribution function, f(N_H I_), at z= 0 using 21-cm HI emission from galaxies selected from a blind HI survey. f(N_H I_) 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_DLA_/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_H I_) to theoretical predictions and analysing contributions to dN_DLA_/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_DLA_/dz however, is much more discriminating. We find that galaxies with log M_H I_< 9.0 make up 34 per cent of dN_DLA_/dz Irregular and Magellanic types contribute 25 per cent; galaxies with surface brightness account for 22 per cent and sub-L_*_ galaxies contribute 45 per cent to dN_DLA_/dz. We conclude that a large range of galaxy types give rise to DLA systems, not just large spiral galaxies as previously speculated. Keywords: galaxies: ISM, quasars: absorption lines =========================================================================== 2005MNRAS.356.1600R Erratum: The column density distribution function at z= 0 from HI selected galaxies [MNRAS,343,1195-1206 (2003)] Ryan-Weber, Emma V.; Webster, Rachel L.; Staveley-Smith, Lister Abstract. {see text} ===========================================================================
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