However, modeling has shown that it is difficult to scatter enough stars toward the black holes to solve the final-parsec problem.
Alternatively, each black hole might have a small disk of gas around it, and these disks might draw in material from a wider disk that surrounds the empty region carved out by the holes. “The disks around them are being fed from the wider disk,” Taylor said, and that means, in turn, that their orbital energy can leak into the wider disk. “It seems a very efficient solution,” Natarajan said. “There’s a lot of gas available.”
In January, Blecha and her colleagues investigated the idea that a third black hole in the system could provide a solution. In some cases where two black holes have stalled, another galaxy could begin to merge with the first two, bringing with it an additional black hole. “You can have a strong three-body interaction,”…
