Optical properties and dynamics of galaxies in the Hickson compact groups

The way in which galaxy properties in dense galaxy environments compare with the properties isolated in the field is presently evaluated in light of broadband R and H-alpha images, as well as H-alpha long-slit spectroscopy, for a set of galaxies (in 21 Hickson compact groups) whose observed velocity patterns range from too peculiar for rotation-curve formation, to abnormal, to normal. A surprisingly high correlation is noted between absolute magnitude and (log) maximum rotation velocity, especially in the case of galaxies with normal rotation curves. These observations support a model in which the compact-group galaxies have only recently accumulated from the general galaxy distribution, and in which tidal interactions are frequent and persisting. 72 refs.