Annu. Rev. Astron. Astrophys. 1991. 29: 581-625 Copyright © 1991 by Annual Reviews. All rights reserved

6.1 Total H₂ Masses

The masses of molecular gas that are derived for galaxies cover a broad range, from 5 x 10¹⁰ M for the most massive (Solomon & Sage 1988, Young et al 1989, Sanders et al 1991) to less than 10⁶ M for some low-mass dwarfs (Tacconi & Young 1987), adopting the same CO -> H₂ conversion constant as for the massive spirals. The range of HI masses found in the same galaxies is similar (Young et al 1989).