Compact groups of galaxies are small associations of several galaxies in close proximity to one another. The galaxies interact gravitationally, which can results in bursts of star formation, nuclear activity, enhanced radio emission, x-ray emission and ultimately merging of the galaxies. Thus, these systems are rich laboratories in which to study the dynamical evolution of galaxies.
My 1982 catalogue identified 100 such systems, which have since been intensively studied at many wavelengths. I continue to maintain an interest in these systems, and the subject of galaxy evolution in general. For further information follow the links below.