Quasars and Active Galactic Nuclei
| Professors: Cui, Giannios, Lister, Lyutikov The most luminous continuous beacons in the the universe are quasars. They are powered by the release of gravitational energy as matter falls onto supermassive black holes at the centers of galaxies. This energy release is far more efficient than the nuclear fusion reactions that power stars, so that quasars can be seen all the way across the observable universe. Quasars and other subclasses of active galactic nuclei emit radiation right across the electromagnetic spectrum, and the X-rays they emit seem to come from the very most central regions, just a few times the size of the event horizon. |
 An artist impression of the quasar 3C120, showing paired jets emerging from a accretion disk that orbits a a supermassive nlack hole. The jet, composed of relativistic plasma, is accelerated and collimated by strong magnetic fields. |