Galaxies with active nuclei that are very luminous and emit both thermal and nonthermal radiation.
a galaxy where a significant fraction of the energy output is not emitted from normal stellar populations or interstellar gas
A galaxy possessing an active galactic nucleus at its center.
a galaxy emitting unusually large amounts of energy from a compact central source
A galaxy which releases large amounts of energy from its centre, the active galactic nucleus. The central engine of an active galaxy probably is a supermassive black hole. Seyfert galaxies, quasars and blazars are active galaxies.
A galaxy which shows explosive activity and can emit large amounts of energy, especially from its central regions.
A galaxy whose center emits large amounts of excess energy, often in the from of radio emission. Active galaxies are suspected of having massive black holes in their centers into which matter is flowing.
galaxies characterized by a large energy output compared to a normal galaxy
A galaxy that is a source of excess radiation, usually radio waves, X-rays, gamma rays, or some combination.
A galaxy that emits much more energy than the sum of the individual stars within it. Such galaxies probably are powered by large, hot accretion disks that encircle supermassive black holes in their cores.
a galaxy that emits huge amounts of energy, a fact that cannot be explained by the mere production of radiation by its stars. This emission, which generally comes from a small region of the galaxy, is today attributed to phenomena such as the growth of matter on a massive black hole situated in the centre of the galaxy.
A "hyperactive" galaxy that emits more energy than sum of the individual stars within it. These galaxies emit energy at wavelengths across the electromagnetic spectrum, from radio to X-ray, and they have powerful, concentrated, non-thermal energy sources at their cores. Some are also unusually bright at radio, infrared or X-ray wavelengths compared to the Milky Way. Three types of active galaxies are Seyfert Galaxies, quasars, and blazars. Many active galaxies are also radio galaxies.
luminous galaxy that produces most of its energy from a very compact source at its center. It has a non-thermal continuous spectrum. The energy is coming from an accretion disk of gas around a supermassive black hole at the nucleus of the galaxy.
A galaxy that radiates large amounts of energy quite differently in character than that of a normal galaxy.