Supermassive black holes hide in the center of massive galaxies, and when two of those galaxies merge, the black holes end up on a collision course. The NGC 7727 pair broke the record for the smallest separation between two supermassive black holes, as they are observed to be only 1600 light-years apart in the sky. "This is the first time that we have found two supermassive black holes that are so close to each other, less than half the separation of the previous record holder," says Karina Voggel, an astronomer at the Strasbourg Observatory in France and lead author of the study. published online today in the journal Astronomy & Astrophysics. "The small separation and speed of the two black holes indicate that they will merge into a monstrous black hole, probably within the next 250 million years," adds co-author Holger Baumgardt, a professor at the University of Queensland, Australia. The merger of black holes like these could explain the process of formation of the most massive black holes in the universe. Voggel and his team were able to determine the masses of the two objects by observing how the gravitational pull of black holes influences the motion of the stars around them. The largest black hole, located right in the core of NGC 7727, was found to have a mass almost 154 million times that of the Sun, while its companion has 6.3 million solar masses.
