While their analysis made use of 121 disk galaxies, the present sample contains mass estimates for over 3000 objects. As with luminosity and size we find, in Figure 2 c , a small systematic variation of total mass among the classical spirals followed by a pronounced decrease for the dwarf systems. In studying the dark matter distribution, HI rotation curves are more suitable given that they generally extend far beyond the point where H is detected, and thus better constrain the halo distribution. He sees a clear indication that the dark matter component increases for the latest types, but along the spiral sequence evidence for significant morphological trends is lacking, partly due to the still-small number of objects mapped. As in Broeils' sample, they do not sample the full range of the spiral sequence.
Classical spirals show rotation curves whose outer portions are rising, flat or falling.
As evident in Figure 3 c , the total mass surface density T shows a clear decrease along the spiral sequence. This page is maintained by Cren Frayer.