Scientists solve long-standing mystery of supermassive black hole mergers 18:02

Canadian scientists from the University of Toronto have found a connection between very large and very small space objects (supermassive black holes and dark matter particles). It turns out that this interaction allows supermassive black holes to merge together. The study was published in the scientific journal magazine Physical Review Letters (PRL).

In 2023, astrophysicists announced that they had discovered a “hum” of gravitational waves permeating space. Experts suggested that this background signal was coming from the merger of millions of supermassive black holes, each billions of times more massive than the Sun.

However, theoretical modelling showed that the approach of the two supermassive black holes stopped at a distance of about three light-years, or one parsec. This phenomenon was called the “last parsec problem” and contradicted the theory that supermassive black holes could merge.

According to experts, the recent parsec problem was caused by the interaction between the clouds or halos of dark matter surrounding supermassive black holes, preventing them from merging together.

In the new study, the team created a model in which the density of dark matter halos remains high enough to interact in such a way that the black holes continue to merge until they merge into a single object.

In addition to providing insight into the background signal of small hole mergers and gravitational waves, the new results also provide a slightly better understanding of the nature of dark matter.
“We found that the evolution of black hole orbits is very sensitive to the microphysics of dark matter, which means we can use observations of supermassive black hole mergers to better understand these particles. “Our work is a new way to help understand the granular nature of dark matter,” said Gonzalo Alonso-Alvarez, one of the authors of the scientific paper.

Earlier scientists discovered oldest merger of twin quasars in deep space.