However, modeling has shown that it is hard to scatter enough stars Toward black holes solving the last-parsec problem.
Alternatively, there may be a small disk of gas around each black hole, and these disks may draw material from a wider disk that surrounds the empty region created by the holes. “The disks around them are being fed by the broader disk, and that means that, in turn, their orbital energy may be leaking into the broader disk,” Taylor said. “This seems to be a very efficient solution,” Natarajan said. “There's plenty of gas available.”
In January, Blecha and colleagues examined the idea A third black hole in the system may provide a solution. In some cases where two black holes have stopped, another galaxy may begin to merge with the first two, bringing with it an additional black hole. “You can have strong three-body interactions,” Blecha said. “This can take away energy and greatly reduce fusion times.” In some scenarios, the lightest of the three holes exits, but in others all three merge.
test on the horizon
The task now is to find out which solution is correct, or whether there are multiple processes running.
Alonso-Alvarez hopes to test his idea by looking for signals of self-interacting dark matter in upcoming Pulsar Timing Array data. Once black holes approach the final parsec, they lose angular momentum primarily by emitting gravitational waves. But if self-interacting dark matter is at work, we should see it absorbing some energy at distances around the parsec limit. This, in turn, would create less energetic gravitational waves, Alonso-Alvarez said.
hi-bo youA particle physicist at the University of California, Riverside who is a Proponents of self-interacting dark matterSaid that this idea is laudable. “This is an opportunity to see subtle features of dark matter from gravitational wave physics,” he said. “I think it's very fascinating.”
The European Space Agency's Laser Interferometer Space Antenna (LISA) spacecraft, a gravitational wave observatory set to launch in 2035. Maybe we'll get more answersLISA will pick up the strong gravitational waves emanating from the merging of supermassive black holes in their final days. “With LISA we will actually see supermassive black holes merge,” Pacucci said. The nature of that signal may reveal “special features that characterize the slow process”, solving the last-parsec problem.
original story Reprinted with permission quanta magazine, An editorially independent publication of Simons Foundation Its mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.