A Dynamical Study of Galaxies in the Hickson Compact Groups

To investigate dynamical properties of spiral galaxies in the Hickson compact groups (HCGs), we present rotation curves of 30 galaxies in 20 HCGs. We found as follows: (1) There is no significant relation between dynamical peculiarity and morphological peculiarity in HCG spiral galaxies. (2) There is no significant relation between the dynamical properties and the frequency distribution of nuclear activities in HCG spiral galaxies. (3) There are no significant correlations between the dynamical properties of HCG spiral galaxies and any group properties (i.e., size, velocity dispersion, galaxy number density, and crossing time). (4) Asymmetric and peculiar rotation curves are more frequently seen in the HCG spiral galaxies than in field spiral galaxies or in cluster ones. However, this tendency is more obviously seen in late-type HCG spiral galaxies. These results suggest that the dynamical properties of HCG spiral galaxies do not strongly correlate with the morphology, the nuclear activity, and the group properties. Our results also suggest that more frequent galaxy collisions occur in the HCGs than in the field and in the clusters.