Active galactic nuclei (AGN) are extremely energetic regions at the centers of some galaxies, powered by supermassive black holes. They emit vast amounts of radiation across the electromagnetic spectrum, often outshining the rest of the galaxy.
Quasar: A highly luminous type of AGN with significant redshift, indicating they are very distant and thus seen as they were in the early universe.
Supermassive Black Hole: A black hole with a mass ranging from millions to billions of times that of our Sun, typically found at the centers of galaxies.
Accretion Disk: The disk-shaped flow of gas, dust, and other material that orbits and gradually falls into a central body like a black hole in an AGN.