Dictionary
radio galaxy
One variety of the active galactic nuclei of young galaxies, whose central region radiates extremely great amounts of energy. Radio galaxies are distinguished by radiating off extremely high energies in the form of radio waves (more than 1035 Watts), from sources that are often located outside the visible part of those galaxies. Usually, the sources are radio bubbles, huge regions of gas whose radiation is stimulated by jets.
To the best of current knowledge, what’s behind all that energy output is a supermassive black hole in the galactic core.