Using the ALMA radio interferometer to study a pair of merging galaxies, a research team found two supermassive black holes growing at the center of the emerging galaxy. This pair would contain the two closest black holes to each other ever observed at multiple wavelengths. Scientists speculate that supermassive black hole pairs are much more common than expected, which would have significant implications for future gravitational wave detections.
500 million light years from Earth, in the constellation Cancer, is an emerging galaxy called UGC4211, generated by the merger of two galaxies. While observing it with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the researchers identified two supermassive black holes growing simultaneously at its center. Thanks to ALMA’s highly sensitive receivers, used to examine the depths of the galactic nuclei involved in the merger, it was possible to detect not one, but many two black holes devouring the smelting products. Remarkably, they are only 750 light-years apart, making them one of the closest pairs of supermassive black holes ever detected. Also, the opportunity to observe these two monstrous celestial giants. at different wavelengths harnessing data from multiple telescopes and astronomical surveys has allowed scientists to take a closer look at the situation. Results of the new research have been published in The Astrophysical Journal Letters and presented at a press conference at the 241st meeting of the American Astronomical Society (AAS) in Seattle, Washington. Michael Koss, Principal Research Scientist at Eureka Scientific and lead author of the new research, said:
Simulations so far have suggested that most of the binary black hole population in nearby galaxies would be inactive. They’re more common than two growing black holes, like the ones we’ve found. But since we know that galaxy mergers are much more common in the distant Universe, these black hole binaries could also be much more common than previously thought. The ALMA radio interferometer: a game changer The use of the ALMA radio interferometer was undoubtedly a turning point. Its sensitivity and performance have made it possible to resolve, or to optically separate, two black holes so close together that, with other instruments, they would hardly appear to be two distinct points. ALMA is unique: it can see through large columns of gas and dust, achieving very high spatial resolution. And, along with other discoveries of this caliber, it will revolutionize our understanding of galaxy mergers, black hole interactions, and consequently future gravitational wave detections.
Ezequiel Treister, an astronomer at the Catholic University of Chile and co-author of the research, said: “There could be many pairs of supermassive black holes growing in the centers of galaxies that we have not been able to identify until now. If this is the case, in the near future we will observe frequent gravitational wave events caused by mergers of these objects throughout the Universe.” To add more detail to this already very compelling discovery, the wavelengths of other powerful telescopes have been exploited: NASA’s Chandra X-ray Space Observatory. NASA Hubble Space Telescope. ESO’s Very Large Telescope with the Multi-Unit Spectroscopic Explorer (MUSE) instrument. the Keck Observatory in the Hawaiian Islands. The 4-meter Blanco Telescope at the Cerro Tololo Inter-American Observatory (CTIO), with the Dark Energy Camera Legacy Survey (DECalS) instrument. Each wavelength tells a different part of the story. While terrestrial optical images showed the entire galaxy merging, Hubble pinpointed the nuclear regions in high resolution.