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Two supermassive black holes have been seen feasting on cosmic materials when two galaxies in distant space merge, and they are the closest black holes to the collision that astronomers have ever observed.
Astronomers spotted the pair while using the Atacama Large Millimeter/Submillimeter Array, or ALMA, telescopes in the Atacama Desert in northern Chile to observe two merging galaxies about 500 million light-years from Earth.
The two black holes were growing in tandem near the center of the coalescing galaxy resulting from the merger. They met when their host galaxies, known as UGC 4211, collided.
One is 200 million times the mass of our sun, while the other is 125 million times the mass of our sun.
While the black holes themselves are not directly visible, both were surrounded by bright clusters of stars and warm, glowing gas, all of which are being pulled in by the holes’ gravitational pull.
Over time, they will start circling in orbit, eventually colliding with each other and creating a black hole.
After observing them through multiple wavelengths of light, the black holes are as close as scientists have ever seen, only about 750 light-years away, which is relatively close, astronomically speaking.
The results were shared at the 241st meeting of the American Astronomical Society which will take place this week in Seattle, and will be published on Monday in The letters of the astrophysical journal.
The distance between the black holes “is pretty close to the limit of what we can detect, which is why this is so exciting,” said study co-author Chiara Mingarelli, an associate research scientist at the Flatiron Institute’s Center for Computational Astrophysics in New York City. NY. , in a sentence.
Galactic mergers are more common in the distant universe, making them harder to see with ground-based telescopes. But ALMA’s sensitivity was able to observe even their active galactic nuclei, the bright, compact regions of galaxies where matter revolves around black holes. Astronomers were surprised to find a binary pair of black holes, rather than a single black hole, eating the gas and dust generated by the galactic merger.
“Our study has identified one of the closest pairs of black holes in a galaxy merger, and because we know that galaxy mergers are much more common in the distant Universe, these black hole binaries may also be much more common than expected. than was previously thought,” he said. the study’s lead author, Michael Koss, a senior research scientist at the Eureka Institute for Scientific Research in Oakland, California, in a statement.
“What we’ve just studied is a source in the final stage of the collision, so what we’re seeing foreshadows that merger and also gives us insight into the connection between the merger and the growth of black holes and eventually, the production of gravitational waves,” Koss said. .
If pairs of black holes, as well as the galaxy mergers that lead to their creation, are more common in the universe than previously thought, they could have implications for future gravitational wave research. Gravitational waves, or ripples in space-time, are created when black holes collide.
It will still take a few hundred million years for this particular pair of black holes to collide, but the insights gained from this observation could help scientists better estimate how many black hole pairs are close to colliding in the universe.
“There may be many pairs of growing supermassive black holes at the centers of galaxies that we have not been able to identify until now,” said study co-author Ezequiel Treister, an astronomer at the Catholic University of Chile in Santiago, Chile, in a statement. “If this is the case, in the near future we will be observing frequent gravitational wave events caused by mergers of these objects throughout the Universe.”
Space telescopes such as Hubble and the Chandra X-ray Observatory and ground-based telescopes such as the European Southern Observatory’s Very Large Telescope, also in the Atacama Desert, and the WM Keck Telescope in Hawaii have also observed UGC 4211 at different wavelengths of light. to provide a more detailed description and differentiate between the two black holes.
“Each wavelength tells a different part of the story,” Treister said. “All these data together have given us a clearer picture of how galaxies like ours turned out to be the way they are and what they will become in the future.”
Understanding more about the final stages of galaxy mergers could provide more information about what will happen when our Milky Way galaxy collides with the Andromeda galaxy in about 4.5 billion years.
