With ESO’s Very Large Telescope (VLT), astronomers discovered six galaxies around a supermassive black hole when the universe was less than a billion years old. This is the first time such a close grouping has been observed shortly after the Big Bang. The new discovery, published in the journal Astronomy & Astrophysics, is helping scientists better understand how supermassive black holes, one of which is in the center of the Milky Way, formed and grew to their enormous size.
The results of the new discovery and research support the theory that black holes can grow rapidly in large, cobweb-like structures that contain a lot of gas to fuel them.
“This research was driven by a desire to understand some of the most complex astronomical objects – supermassive black holes in the early universe. These are extreme systems, and today we do not have a decent explanation for their existence, ”says Marco Mignoli, astronomer at the National Institute of Astrophysics (INAF) in Bologna, Italy.
New observations with ESO’s VLT have revealed several galaxies surrounding the supermassive black hole, all of which are in the cosmic web of gas that stretches over vast distances – 300 times the size of the Milky Way. “The strands of the cosmic web are like the strands of a regular web,” explains Mignoli. “Galaxies stand and grow where these filaments intersect, and streams of gas that can feed both galaxies and the central supermassive black hole can flow through them.”
Light from this large cobweb-like structure with a black hole weighing 1 billion solar masses has reached Earth since the universe was only 0.9 billion years old. “Our work has placed an important element in the unfinished puzzle of the formation and growth of such extreme but numerous objects so soon after the Big Bang,” study co-author Roberto Gilly, an astronomer at INAF in Bologna, said, referring to supermassive black holes.
The very first black holes, believed to have formed from the collapse of the first stars, had to grow very rapidly to reach the mass of a billion suns during the first 0.9 billion years of the universe’s life. But astronomers have struggled to explain how they could have had enough “fuel” available to allow these objects to grow to such enormous sizes in such a short time. The discovered structure offers a plausible explanation: the cobweb and the galaxies within it contain enough gas to provide the fuel the central black hole needs to quickly become a supermassive giant.