Radio telescopes have confirmed that supermassive black holes living in galactic centers are capable of creating pairs during a galactic fusion.
To do this, we studied the found double black hole in a spiral-type galaxy NGC 7674, located 400 million light years away. The distance between them is less than a light year. Their total mass is about 40 million times the solar one, and the orbital period of the system reaches 100,000 years.
Small black holes form when creating supernovae. Impacts between this type led to the discovery of gravitational waves in 2015. These objects were 29 and 36 times larger than our star and distant by 1.3. billion light years. But supermassive black holes create gravitational waves with a lower frequency, so LIGO does not notice the signal. To remedy the situation, the researchers decided to combine all terrestrial telescopes and get an overview exceeding the angular resolution of the human eye 10 million times.
This helped to notice in the center of NGC 7674 two radio sources associated with massive black holes, which confirms the theory.