An active galactic nucleus (AGN) is a highly energetic, compact source of luminosity found at the center of some galaxies. These objects are powered by the gravitational accretion of matter onto a supermassive black hole residing at the galactic core. As surrounding gas and stellar debris spiral inward toward the central singularity, the intense friction and gravitational forces convert gravitational energy into vast amounts of radiation, which spans the entire electromagnetic spectrum, from radio waves to high-energy gamma rays. The feeding process often drives powerful bipolar jets of highly collimated plasma outward from the central engine, which can propagate far into the intergalactic medium, thereby influencing the evolution and structure of the host galaxy itself.