Next Section: Introduction

An HI selected sample of galaxies -- The HI mass function and the surface brightness distribution

Martin Zwaan, Frank Briggs and David Sprayberry
Kapteyn Astronomical Institute
P.O. Box 800, NL-9700 AV Groningen, The Netherlands
zwaan@astro.rug.nl, fbriggs@astro.rug.nl, dspray@astro.rug.nl

Abstract:

Results from the Arecibo HI Strip Survey, an unbiased extragalactic HI survey, combined with optical and 21cm follow-up observations, determine the HI Mass Function and the cosmological mass density of HI at the present epoch. Both are consistent with earlier estimates, computed for the population of optically selected galaxies. This consistency occurs because, although the distribution of optical central surface brightnesses among galaxies is flat, we fail to find a population of galaxies with central surface brightnesses fainter than 24б B-, even though there is no observational selection against them.

Keywords: Galaxies: Luminosity Function, Mass Function; Surveys

б© Copyright Astronomical Society of Australia 1997