Astronomers including one of the Indian-origin have identified five pairs of supermassive black holes, each containing millions of times the mass of the Sun, in the centres of galaxies.
This could help astronomers better understand how giant black holes grow and how they may produce the strongest gravitational wave signals in the universe.
These black hole couples formed when two galaxies collided and merged with each other, forcing their supermassive black holes to comes closer to each other.
The black hole pairs were discovered by combining data from a suite of different observatories including
NASA's Chandra X-ray Observatory,
The Wide-Field Infrared Sky Explorer Survey (WISE)
The ground-based Large Binocular Telescope in Arizona.