A galaxy which emits a huge amount of energy from a compact central source. Active Galactic Nuclei

The central regions of some galaxies that appear as point-like sources of radiation. Believed to be supermassive black hole s accreting nearby matter.

a core region in certain galaxies that, like a powerful engine, spews large amounts of energy from its center.

The centers of active galaxies that are emitting large amounts of excess energy.

A galaxy with an unusually bright central region thought to contain a supermassive black hole actively pulling in tremendous amounts of matter from a swirling disk of gas, stars, and dust.

the exceptionally bright cores of some galaxies, thought to be fueled by matter falling into supermassive black holes

A class of galaxies that expell massive amounts of energy from their centers, far more than ordinary galaxies. Many astronomers believe supermassive black holes may lie at the center of these galaxies and power their explosive energy output.

the tiny central engine (likely a supermassive black hole) that drives the active galaxy phenomenon

Central regions of active galaxies that radiate huge quantities of energy quite unlike that of the bulk of normal galaxies. See also "active galaxy" and "nucleus (2)."