Dark matter could provide the brakes that supermassive black holes need to crash into each other at the end of their long, spiraling journeys toward their destiny.
New mathematical modelling suggests that the conundrum known as the Final Parsec Problem can be solved by the presence of self-interacting dark matter particles that remain clustered around black holes, allowing them to cross the final distance between them.
The discovery suggests that the mysterious matter that gives the universe its extra gravity must be able to interact with itself, as models of dark matter that cannot interact with it do not solve the problem.
“When we take into account the previously overlooked influence of dark matter, we find that it helps supermassive black holes overcome this final parsec separation and merge.” To tell “Our calculations explain how this could happen, in contrast to what was previously thought,” said Gonzalo Alonso-Alvarez, a physicist at the University of Toronto and McGill University.
Supermassive black holes at the centers of galaxies pose great mysteries to astronomers. Smaller black holes are known to form from the collapsed cores of massive stars that ran out of nuclear fusion fuel at the end of the universe. These smaller masses can merge with larger ones. The most massive black hole merger detected to date produced an object with a mass equivalent to 142 suns.
Supermassive black holes can be millions to billions of times the mass of our sun. It makes sense that they get that big by merging with other monster black holes. Throughout the history of the universe, supermassive black holes have been seen orbiting each other after galaxies have merged, seemingly on a course to eventually collide.
But it’s not clear how these supermassive black holes collide. Models suggest that as supermassive black holes orbit each other, they transfer their orbital energy to the surrounding stars and gas, causing their orbits to become smaller and smaller. As the black holes get closer together, there is less material to steal their momentum from.
Once they’re about one parsec apart (about 3.2 light years), the surrounding galaxy can no longer tolerate further orbital decay, and the black hole’s orbit becomes stable for a very long time. How long? At least longer than it has been since the beginning of the universe.
One way to test whether supermassive black holes have indeed merged in the past is to use gravitational waves – giant ripples in the fabric of space-time that occur when large masses change speed. If supermassive black holes are colliding throughout the universe, there should be a distinctive background sound of very low frequency gravitational waves rippling constantly throughout the universe.
Finally, they detected the sound of background gravitational waves, suggesting they had missed a key part about the collision of supermassive black holes.
this is The Final Parsec Problem.
It could be that we’re missing dark matter, but current models of supermassive black hole merging suggest that their gravitational interactions should also eject dark matter particles from the system that could absorb the final orbital energy.
Now, the problem with dark matter is that we don’t know what it is. Dark matter doesn’t interact with the normal matter in the universe except through gravity, making it very difficult to study. We call it dark matter as a working term, but scientists are trying to figure out its properties by studying the behavior of the universe in other ways.
frameborder=”0″ allow=”Accelerometer; Autoplay; Clipboard writing; Encrypted media; Gyroscope; Picture-in-picture; Web sharing” referrerpolicy=”strict-origin-when-cross-origin” allowfullscreen>
Alonso Alvarez and his colleagues wondered if it was too early to discard dark matter as a solution, so they designed a mathematical model to test it. Interact with yourself They can remain close to the merging supermassive black holes, giving the black holes a place to pass on their final orbital energy so they can eventually merge and form a single supermassive black hole.
At the moment, the results are fairly theoretical, but they do point to observable predictions. For example, the discovery predicts a weakening of the gravitational wave background, which has already been signaled. The results can also be used to understand the dark matter halos that surround galaxies throughout the Universe, since particles need to interact on a galactic scale to solve the final parsec problem.
Finally, the researchers say their discovery could provide a new tool to unlock the mysteries of dark matter.
“Our study is a new way to help understand the particle nature of dark matter.” To tell “We found that the orbital evolution of black holes is very sensitive to the microphysics of dark matter, which means that observing the mergers of supermassive black holes can help us understand these particles better,” Alonso Alvarez said.
This study Physics Review Letter.
