Active Galactic Nucleus
Active Galactic Nucleus (AGN) is a compact region at the center of a galaxy that emits a high amount of energy, often outshining the rest of the galaxy. AGNs are powered by accretion of mass onto a supermassive black hole, leading to the release of large amounts of energy in the form of radiation and particle jets. AGNs can exhibit various phenomena such as strong radio emission, X-ray emission, and variability in brightness. They play a crucial role in the evolution of galaxies and are believed to be responsible for regulating the growth of galaxies through feedback processes.