A team of astronomers confirmed the existence of a relatively tight pair of supermassive black holes in a nearby galaxy, using the European Southern Observatory’s Very Large Telescope. They are located in the galaxy NGC 7727 in the constellation Aquarius, at about 89 million light-years away from Earth. The two black holes are 1,600 light-years apart. “It is the first time we find two supermassive black holes that are this 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. “The small separation and velocity of the two black holes indicate that they will merge into one monster black hole, probably within the next 250 million years,” adds co-author Holger Baumgardt, a professor at the University of Queensland, Australia. The bigger black hole, located right at the core of NGC 7727, was found to have a mass almost 154 million times that of the Sun, while its companion is 6.3 million solar masses.
Experts were able to determine these masses by looking at how the gravitational pull of the black holes influences the motion of the stars around them. Astronomers suspected that the galaxy hosted the two black holes, but they had not been able to confirm their presence until now. This pair of merging black holes is the closest to Earth we’ve ever found. The search for similarly hidden supermassive black hole pairs is expected to make a great leap forward with the new Extremely Large Telescope (ELT), which is set to start operating later this decade in Chile’s Atacama Desert.