Supermassive black holes act as engines that power the centers of galaxies, including our galaxy, the Milky Way. But, for the first time in history, an international team of astronomers led by scientists from the universities of Göttingen and Potsdam, has observed that a galaxy contains three supermassive black holes at its core and that they are surprisingly close together.
That’s how it is. We have found the first known galaxy to have three supermassive black holes.
The irregular galaxy, NGC 6240, which is relatively close, 300 million light-years away, has an unusual shape, which previously led scientists to believe that it formed when two smaller galaxies collided and began to merge.
Due to its “closeness”, experts have been able to study it at all wavelengths of light. It was seen as a standard for galactic interaction and scientists thought that due to the merger, there were probably two black holes at its core. However, what was not their surprise when they identified a third supermassive black hole in the center of the galaxy. Each of them has the mass of more than 90 million suns, according to observations made by the Very Large Telescope of the European Southern Observatory in Chile (ESO).
This new finding suggests that not two, but three galaxies are in the process of merging, each contributing its own supermassive black hole galactic core.
“Through our observations with extremely high spatial resolution,” explained astrophysicist Wolfram Kollatschny of the University of Göttingen in Germany, “we were able to show that the interactive galaxy system NGC 6240 harbors not two, as previously assumed, but three holes. supermassive blacks at its center. “
For comparison, the supermassive black hole at the center of the Milky Way, Sagittarius A *, weighs about 4 million solar masses. Furthermore, the three giant black holes in NGC 6240 lie in a region less than 3,000 light-years across, which is less than 1% the size of the galaxy in which they reside . They are incredibly together.
“Until now, such a concentration of three supermassive black holes had never been discovered in the universe,” said Peter Weilbacher of the Leibniz Institute for Astrophysics Potsdam, a co-author of the study. Although astronomers have previously found three separate galaxies and their associated black holes on a collision course before, this is the first time they have witnessed supermassive black holes crammed into such a small space.
The discovery of this triple system is of fundamental importance to understand the evolution of galaxies over time. Until now it has not been possible to explain how the largest and most massive galaxies, known to us from our cosmic environment at the “present time”, were formed solely by the interaction of normal galaxies and fusion processes over the course of time. 14,000 million previous years; that is, the age of our universe. “However, if there were simultaneous mergers of several galaxies, then the larger galaxies with their central supermassive black holes could evolve much faster, ” concludes Peter Weilbacher. “Our observations provide the first indication of this scenario.”
The finding is not only a strange, exciting and unprecedented discovery, it also shows how several galaxies can come together simultaneously to build the largest galaxies in the universe. Of course, we will have to wait another billion years, at least, for this triple fusion to take place. Will humanity still be here to see it?
The study has been published in the journal Astronomy & Astrophysics .
Referencia: W. Kollatschny et al, NGC 6240: A triple nucleus system in the advanced or final state of merging, Astronomy & Astrophysics (2019). DOI: 10.1051/0004-6361/201936540
