The LIGO collaboration announced the detection of the largest black hole merger ever observed using gravitational waves. The signal, designated GW231123, was received on November 23, 2023 and comes from the merger of two supermassive black holes — with an approximate mass of 137 and 103 solar masses. The resulting black hole has a mass of more than 225 solar masses, making it the largest such event recorded to date. This is reported by Gizmodo.
According to the scientists, this merger "should not have happened" according to standard models of stellar evolution. In particular, it is believed that black holes of this mass cannot form as a result of the collapse of a single star, and the formation of such binary systems from such objects is considered extremely unlikely.
"This merger challenges our understanding of how black holes form," said physicist Mark Hannam of Cardiff University. One theory is that both black holes could themselves have been the result of previous mergers, creating what is known as a "hierarchical system."
Another feature was the rapid rotation of both objects, which almost reached the limits allowed by general relativity. This greatly complicated the mathematical modeling of the signal, which lasted only 0.1 seconds but contained an enormous amount of information.
"This is a great example of how extreme phenomena can push the boundaries of our theoretical understanding of the universe," commented Charlie Goy from the University of Portsmouth.
The observations were made using three detectors: LIGO in the US, Virgo in Italy and KAGRA in Japan. These observatories have recorded hundreds of such events in recent years, but GW231123 is the most powerful ever recorded.
The results will be formally presented at the GR24 and Edoardo Amaldi International Gravitational Wave Conference in Glasgow. The data will also be made available for analysis by the scientific community. The researchers estimate that it could take years to fully decipher this signal, and it is possible that it will lead to new discoveries in black hole physics.