Science and Technology **Beijing, March 3 (Reporter Liu Xia) Using archival data from the North Gemini Telescope, American astronomers have discovered the heaviest supermassive black hole pair known to date, with a "weight" of 28 billion times the mass of the sun. The discovery helps scientists unravel a long-standing mystery about why supermassive black hole mergers are so rare in the universe. Related**Published in the latest issue of the Astrophysical Journal.
The research team analyzed the pair of supermassive black holes located within the elliptical galaxy b2 0402+379. This is the only pair of supermassive black holes that has been analyzed in sufficient detail, and the two black holes are only 24 light-years apart. The proximity of these two black holes is a sign that they may undergo a powerful merger. But further research has shown that the pair of black holes have stayed at this distance for more than 3 billion years.
* To better understand the dynamics of the system and why it didn't merge, they consulted archival data from the Northern Gemini Telescope to determine the velocities of stars near the black hole, and deduced that the pair had a total mass of 28 billion times that of the Sun, the heaviest black hole pair ever measured, according to co-author Roger Romani, a professor of physics at Stanford University.
According to the research team, the results not only provide valuable information for studying the formation of binary black hole systems and the history of their host galaxies, but also support a long-standing theory that the mass of supermassive black hole pairs is the key to preventing their merger.
Normally, galaxies with lighter pairs of black holes appear to have enough stars and mass to merge the two, such as in 2015, when scientists detected a merger of star-mass black holes through gravitational waves. But since this pair of black holes is very heavy, it takes a lot of stars and gas to do the job. Given the lack of sufficient material in the b2 0402+379 galaxy to do this, the merger of the pair of black holes has stalled.
Romani points out that it remains to be determined whether the pair of black holes will eventually merge on a timescale of millions of years. If they merge, the resulting gravitational waves will be 100 million times stronger than those of stellar-mass black holes.