Galaxy Evolution in a New Southern Compact Groups Sample

Abstract

Compact groups are association of 4-8 galaxies with high spatial densities (δρ/ρ ∼ 10−20), but low velocity dispersion. Galaxy-galaxy interactions (e.g. close tidal encounters or mergers) are therefore likely to dominate any environmentally-dependent evolution of galaxies in these compact, high local-density groups, unlike in the field, where galaxy densities are too low, and in clusters, where relative velocities are too high. We present here the results from spectroscopic and photometric observations of a new sample of compact groups in the Southern Sky, selected by an automatic detection algorithm applied to a digitized galaxy database.