Active galaxy, illustration. Active galaxies are those with an active galactic nucleus (AGN), driven by a central supermassive black hole. AGNs emit a range of non-stellar radiation, including radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray radiation. The features commonly seen in an AGN are an accretion disc around the central supermassive black hole, and relativistic jets (red-orange), which are beams of ionised matter accelerated close to the speed of light. Also shown here are wide-angle outflows (grey-blue).