Linked from
The 35 pages that link to Supermassive black hole, each with the reason it gives.
QuasarBroader topic: Its gravity anchors the compact engine at the center of a quasar.
GalaxyBroader topic: Its growth and energy output can affect gas in the central galaxy.
Messier 87Broader topic: M87’s central black hole has a mass of about 6.5 billion Suns.
Messier 81Broader topic: A supermassive black hole powers activity in M81’s central region.
Reinhard GenzelBroader topic: The inferred central mass places Sagittarius A* in this class.