Researchers found that dark matter particles play a key role in helping supermassive black holes merge, resolving the “final parsec problem” in astronomy. In 2023, scientists detected gravitational waves from merging black hole pairs. But simulations showed a halt in their approach when about three light years apart, which contradicted theories that these mergers create the observed gravitational wave background and that SMBHs grow by merging less massive black holes. Study co-author Gonzalo Alonso-Álvarez explained that previously overlooked interactions between dark matter particles keep them from being dispersed, allowing for continued spiral inward and eventual merger. The team’s new model suggests that only dark matter models with this interaction can explain the final parsec problem. The researchers also predict that gravitational waves observed by pulsar timing arrays should have a softened spectrum at low frequencies, which current data hints at and may be confirmed in the next few years. This discovery offers insights into SMBH mergers, dark matter’s nature, and the interplay between dark matter and cosmic structures.
Source: https://www.earth.com/news/dark-matter-might-be-driving-force-behind-black-hole-mergers/