The new discovery suggests that binary supermassive black holes may be much more common than previously thought. The finding is a preview of what could happen when our galaxy merges with Andromeda in the future.
500 million light years from Earth, in the constellation of Cancer, 2 supermassive black holes feed together as a result of a gigantic collision of galaxies. Both are only 750 light-years away from each other, growing frantically as their host galaxies merge.
An international team of astronomers was able to discover two such colossi “dining” at such a close distance for the first time, thanks to the ALMA observatory and the use of a combination of ground-based and space-based telescopes.
As part of an investigation in which they had a leading role CATA astronomers from the Catholic University and the Diego Portales Universityit was possible to observe this pair of nearby and active black holes. Both penetrate through the large clouds of dust and gas resulting from the galactic merger known as UGC4211.a barrier that until now had not allowed them to be identified.
The results, published today in the journal The Astrophysical Journal Letters and announced at a press conference organized by the American Astronomical Society, will allow us to better understand what will happen when the Milky Way collides with the neighboring Andromeda galaxy.
In addition, point out that binary black holes – and the colliding galaxies that cause them – could be surprisingly common phenomena In the universe.
Ezequiel Treister, an astronomer at the Catholic University and co-author of the study, indicates that the finding would also have implications for the detection of gravitational waves.
“There may be many pairs of growing supermassive black holes in the centers of galaxies that we have not yet been able to identify. In that case, in the near future we will observe frequent gravitational waves generated by the mergers of these objects throughout the Universe. Thanks to future space observatories like LISA.”
2 black holes as a puzzle in a galaxy clash
According to the astronomer and deputy director of CATA, the new finding was possible thanks to the combination of data from the ALMA radio telescope with observations at multiple wavelengths from other powerful telescopes. Among them NASA’s Chandra and Hubble, ESO’s Very Large Telescope and the Keck Observatory in Hawaii.
“Each wavelength shows a different part of the picture, like a giant puzzle,” explains Treister.
In this way, while the optical images obtained with terrestrial observatories showed the entire colliding galaxy, the Hubble telescope made it possible to observe the nuclear regions in high resolution.
At the same time, X-ray observations revealed that there was at least one active galactic nucleus in the system. “ALMA showed us the exact location of these 2 supermassive and gluttonous black holes in full growth“, highlights Ezequiel Treister.
Thus managed to penetrate to the depths of the active galactic nuclei of the fusion UGC4211explains Claudio Ricci, a UDP-CATA astronomer who participated in the research. “These are areas of the galaxies that are difficult to access because they are compact and extremely luminous, generated by the accretion of matter around the central black holes.”
The astronomer tells that surprisingly while they were investigating with ALMA, the science team discovered not one, but two black holes frantically devouring fusion byproducts. “And they were both feasting very close to each other: just 750 light-years away,” adds Ricci.
Future of the Milky Way
Franz Bauer, a UC-CATA astronomer who also participated in the research, points out that With this new information, astronomers will be able to have a clearer idea about how galaxies similar to ours have become what they are now. and how they will continue to evolve.
“Until now, the first stages of galaxies merging had mainly been studied, but the new observations correspond to the last stages of a collision, a preview of what will happen when the Milky Way collides with the neighboring Andromeda galaxy. In about 4,500 million years.
The astronomer adds that previous simulations indicated that most binary black holes in nearby galaxies must be inactive objects. “But we were able to observe a pair of black holes in full growth,” she said.
Michael Koss, a senior researcher at Eureka Scientific and lead author of the study, noted that “we have identified one of the closest pairs of black holes that we know of in a colliding galaxy“.
“And since we know that these galaxy mergers are much more common in the distant Universe, we can assume that these binary black holes could also be much more common than previously thought,” he concluded.