Some astronomers have begun labeling black holes of at least 10 billion M ☉ as ultramassive black holes. Supermassive black holes are classically defined as black holes with a mass between 0.1 million and 10 billion M ☉. Two supermassive black holes have been directly imaged by the Event Horizon Telescope: the black hole in the giant elliptical galaxy Messier 87 and the black hole at the Milky Way’s center. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering active galactic nuclei and quasars. For example, the Milky Way has a supermassive black hole in its Galactic Center, corresponding to the radio source Sagittarius A*.

Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, not even light. The image was released in 2019 by the Event Horizon Telescope Collaboration.Ī supermassive black hole ( SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of millions to billions of times the mass of the Sun ( M ☉). The dark center is the event horizon and its shadow. It shows radio-wave emission from a heated accretion ring orbiting the object at a mean separation of 350 AU, or ten times larger than the orbit of Neptune around the Sun.

This is the first direct image of a supermassive black hole, located at the galactic core of Messier 87.

Massive blackhole