Astronomers have discovered a pair of supermassive black holes close to colliding. This was reported by the press service of the Simons Foundation.
These black holes are 750 light-years apart and will not merge for another few hundred million years. However, this is the closest to any merger seen before by astronomers. Because of the small distance between the black holes, astronomers were able to distinguish the two objects by combining rich data from seven telescopes, including Hubble. Supermassive black holes cannot be seen directly with an optical telescope: they are surrounded by bright star clusters and gravitationally heated hot gas.
The mass of the detected objects is 200 and 125 million solar masses, the distance from the Earth is about 480 million light years. Supermassive black holes are at the center of most galaxies and grow by engulfing surrounding gas, dust, stars, and even other black holes. Galaxies collide with each other as they pass through each other or merge. Over the next million years, the discovered objects will orbit each other in lower and lower orbits as the dust and gas around them absorb the energy of orbital motion. After a while, these black holes will start producing the strongest gravitational waves and will eventually merge into a single wave.
In the future, astronomers hope to capture gravitational waves from similar events at a later stage.