In a groundbreaking revelation, American astronomers, utilizing archival data from the Northern Gemini Observatory, have identified the heaviest known pair of supermassive black holes to date, weighing in at a staggering 280 billion times the mass of our Sun. This discovery promises to shed light on a longstanding cosmic mystery: why the occurrence of mergers involving supermassive black holes is a rare phenomenon in the universe. The findings have been published in the latest issue of "Astrophysical Journal."
The research team conducted an in-depth analysis of a pair of supermassive black holes located within the elliptical galaxy B2 0402+379. This particular pair is the only one analyzed in sufficient detail, with a mere 24-light-year separation between the two black holes. The close proximity suggests the potential for a powerful merger, yet further investigation revealed that these black holes have remained at this distance for over 3 billion years.
Co-author of the paper and Stanford University Physics Professor, Roger Romani, stated that to better comprehend the dynamics of this system and the reasons behind their non-merger, they delved into the archival data of the Northern Gemini Observatory. They determined the velocities of stars near the black holes, inferring a total mass of 280 billion times that of the Sun, marking it as the heaviest black hole pair measured to date.
The research team emphasized that this measurement not only provides valuable data for understanding the formation of binary black hole systems and the history of their host galaxies but also supports a long-standing theory that the mass of supermassive black hole pairs is a crucial factor preventing their merger.
Typically, galaxies with lighter black hole pairs seem to have enough stars and mass for their merger. For instance, in 2015, scientists detected the merger of stellar-mass black holes through gravitational waves. However, due to the substantial mass of B2 0402+379's black hole pair, a significant amount of stars and gas would be required for the merger to occur. Given the lack of sufficient material within the galaxy, the merger of this black hole pair remains at a standstill.
Romani pointed out that the ultimate merger of these black holes over a timescale of millions of years is still uncertain. If they do merge, the gravitational wave intensity produced would be a hundred million times greater than that of stellar-mass black hole mergers.
