Rotation curves for spiral galaxies in clusters. I. Data, global properties, and a comparison with field galaxies

Rotational velocities have been obtained for 21 galaxies in the large spiral-rich clusters Cancer, Hercules, Peg I, and DC 1842-63. It is noted that the larger, brighter, more massive spirals which are rare in the field are absent in the cluster spirals. Falling rotation curves have been found. The amplitudes of the rotation curves for the nine Sa and Sb galaxies considered are shown to be lower than those of their field counterparts. The results indicate that galaxies which are H I deficient have rotation curves which are most depressed in comparison with field spirals of equivalent Hubble type and luminosity. 55 references