The Centaurus A/M83, divided into subgroup Cen A and M83, is a complex group of galaxies located within Hydra, Centaurus, and Virgo constellations. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered around Centaurus A, a nearby radio galaxy. The M83 Subgroup, at a distance of 14.9 Mly (4.56 Mpc), is centered around the Messier 83 (M83), a face-on spiral galaxy.
Due to the physical closeness of both subgroups they are sometimes identified as two groups sometimes as one. Both subgroups appear not to be moving relative to each other. The Centaurus A/M83, along with the local group, is part of the Virgo Supercluster.
Although the brightest group members were frequently spotted in early galaxy group surveys the dwarf galaxies were not identified until more intensive studies took place.
Through use of the UK Schmidt Telescope and the Parkes Radio Telescope 20 dwarf galaxies were identified as members. 5 un-catalogued and 5 previously catalogued galaxies were identified by the HIPASS survey, which was a blind radio survey for hydrogen spectral line emission. One other dwarf galaxy was found by the HIDEEP survey, which was a more intensive version of HIPASS. Due to coordinate confusion and wrong redshift literature the true identity of the Cen A group remained hidden until 2007 when the group membership of NGC 5011C was established.