Two supermassive black holes discovered in collision-created “fossil galaxies” are so big that they do not collide or merge. This black hole system is located within the elliptical galaxy B2 0402+379. When the two black holes were weighed together, astronomers discovered that they were 28 billion times heavier than the sun. As a result, this is the largest gigantic black hole binary discovered to date. Furthermore, the binary components of the black hole system are the nearest in this supermassive black hole pair, with only 24 light-years separating them.
The vast amount of mass at the centre of the two supermassive black holes shows that they were formed by a series of mergers
Scientists for the first time viewed a supermassive black hole pair in such detail and attempted to study the two objects separately. Interestingly, while the black holes’ proximity suggests that they should crash and merge, they appear to have been trapped in the same orbital dance for more than three billion years. The team of scientists who discovered the binary in data acquired by the Gemini North observatory in Hawaii assumed that the supermassive black holes were prevented from merging due to their enormous mass. “Normally, it seems that galaxies with lighter black hole pairs have enough stars and mass to drive the two together quickly,” said Roger Romani, a member of the team and physics professor at Stanford University, in a statement.
“Since this pair is so heavy, it required lots of stars and gas to get the job done. But the binary has scoured the central galaxy of such matter, leaving it stalled,” he added. B2 0402+379 is a “fossil cluster” which helps scientists understand what occurs when the stars and gas of an entire galaxy cluster merge and form one single massive galaxy. The vast amount of mass at the centre of the two supermassive black holes shows that they were formed by a series of mergers between smaller black holes as numerous galaxies in the cluster collided. Scientists believe that in the centre of most galaxies is a supermassive black hole with a mass equivalent to millions or billions of suns.