Hickson Compact Groups
The Hickson Compact Groups (1982), compiled by Paul Hickson, are a selection of 100 small galaxy groups that show strong mutual interaction due to their extreme compactness. Each group contains a handful of galaxies with very small angular separation, making them ideal laboratories for studying tidal effects, mergers and the dynamical evolution of galaxies in dense environments. The catalogue is a curated list, chosen specifically for its strikingly tight configurations rather than for brightness or observational accessibility.
