Supermassive black hole + supermassive black hole = super-SUPERmassive black hole!
Supercomputer models of merging black holes reveal properties that are crucial to understanding future detections of gravitational waves. This movie follows two orbiting black holes and their accretion disk during their final three orbits and ultimate merger. Redder colors correspond to higher gas densities.
To read more about this phenomenon, read the article over at Universe Today right here.