All galaxies emit high volumes of energy, however active galaxies release a great deal more energy than normal. This high amount of excess energy in active galaxies is found in regions of the electromagnetic spectrum—specifically in the radio, infrared, ultraviolet, and x-ray regions—and can be accounted for the supermassive black holes in their centers that draw in excess materials until the materials spin and create a disk, called the accretion disk. This accretion disk heats up from the frictional and gravitational forces at work, thus creating the excess energy that normal galaxies don't have. Read More…
The links below describe some of the properties of active galaxies.
Galaxies with active nuclei (AGN), classically exhibit all or most of the following characteristics: High luminosity, greater than 1037 W Nonthermal radio source (synchrotron) with excessive UV, IR, radio, and X- ray flux as compared to an ordinary galaxy Small region of rapid variability, exhibiting significant variations over time periods of months or less, in the galactic nucleus High brightness in nuclear region as compared to other regions of the galaxy Jet-like protuberances Broad emission lines (sometimes) Processes found in Active Galaxies include:
Synchrotron Radiation Emission lines The central region of the Milky Way galaxy has several of these characteristics, although the total energy output is well below that generally expected for an AGN.