Free Astronomy Magazine March-April 2022

52 ASTRO PUBLISHING Observatory in France and lead au- thor of the study published in As- tronomy & Astrophysics . “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, Aus- tralia. The merging of black holes like these could explain how the most massive black holes in the Uni- verse come to be. Voggel and her team were able to determine the masses of the two ob- Closest pair of supermassive black holes uncovered by ESO - Bárbara Ferreira U sing the European Southern Observatory’s Very Large Tele- scope (ESO’s VLT), astronomers have revealed the closest pair of su- permassive black holes to Earth ever observed. The two objects also have a much smaller separation than any other previously spotted pair of su- permassive black holes and will even- tually merge into one giant black hole. Located in the galaxy NGC 7727 in the constellation Aquarius, the supermassive black hole pair is about 89 million light-years away from Earth. Although this may seem distant, it beats the previous record of 470 million light-years by quite some margin, making the newfound supermassive black hole pair the clos- est to us yet. Supermassive black holes lurk at the centre of massive galaxies and when two such galaxies merge, the black holes end up on a collision course. The pair in NGC 7727 beat the record for the smallest separation between two supermassive black holes, as they are observed to be just 1600 light-years apart in the sky. “It is the first time we find two su- permassive 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 T his image shows close-up (left) and wide (right) views of the two bright galactic nuclei, each housing a supermassive black hole, in NGC 7727, a galaxy located 89 million light- years away from Earth in the constellation Aquarius. Each nucleus consists of a dense group of stars with a supermassive black hole at its centre. The image on the left was taken with the MUSE instrument on ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile while the one on the right was taken with ESO’s VLT Survey Telescope. [ESO/Voggel et al.; ESO/VST ATLAS team. Acknowledgement: Durham University/CASU/WFAU]