Quasars are the brightest objects in the cosmos and could help astronomers find rare pairs of supermassive black holes. Scientists have long known that supermassive black holes exist at the center of large galaxies, but finding binary pairs of these massive objects has been a challenge. However, new research suggests that galaxies with quasars, which are powered by supermassive black holes, may be more likely to host these elusive binary pairs.
The study, led by Andrew Casey-Clyde from the University of Connecticut and Yale University, found that quasars could be seven times more likely to have supermassive black hole binaries compared to other galaxies. This discovery could revolutionize the search for these binary pairs using gravitational waves, which were first predicted by Einstein’s theory of general relativity in 1915.
Supermassive black hole binaries are formed when galaxies collide, bringing two supermassive black holes into close proximity. Quasars, which are powered by feeding black holes, can indicate the presence of these binary pairs. The research team used a combination of electromagnetic observations of quasars and gravitational wave detections to study these cosmic phenomena, a method known as multi-messenger astronomy.
Surprisingly, the study found that brighter quasars are less likely to host supermassive black hole binaries than fainter ones. This is because the brightest binary quasars are associated with the most massive black hole binaries, which are rarer and merge quickly. Lower mass supermassive black hole binaries, on the other hand, are more likely to be detected by pulsar timing arrays.
The team’s next steps include targeted gravitational wave searches to detect widely separated black hole pairs and better understand the relationship between quasars and galaxy mergers. The Legacy Survey of Space and Time conducted by the Vera C. Rubin Observatory will play a crucial role in improving constraints on the binary quasar population in the coming decade.
This groundbreaking research has been posted as a pre-peer-reviewed paper on the repository site arXiv. The findings open up new possibilities for studying supermassive black hole binaries and could provide valuable insights into the evolution of galaxies and the universe as a whole.
