Active galactic nucleus. Illustration of the thick ring of dust (opaque torus, orange) that can obscure the energetic processes that occur near the supermassive black hole of an active galactic nucleus (AGN). Studies by SOFIA (Stratospheric Observatory for Infrared Astronomy) suggest that the dust distribution around AGNs is about 30 percent smaller than previously thought. 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 the opaque torus, an accretion disc (yellow) around the central supermassive black hole, and relativistic jets (blue), which are beams of ionised matter accelerated close to the speed of light. |