Children of the cosmic web: The seeds of super-massive black holes
Computer simulation shows the seeding of super-massive black holes is a natural by-product of the formation of the cosmic web.
Super-massive black holes which are billion of times more massive than the sun have been detected at the centres of galaxies across the Universe. Most famously our own Milky-Way hosts a super-massive black hole a few million times the mass of the sun at its centre. Despite all this evidence for their existence, the origin of super-massive black holes is an unsolved open question in astrophysics.
A team of international researchers including Professor Sadegh Khochfar from the School’s Institute for Astronomy used 2 million processor hours on super-computers in the UK to show for the first time that that the seeding of super-massive black holes is a natural by-product of the formation of the cosmic web in a Universe dominated by dark energy and cold dark matter. The results provide an answer to the long-standing question on the seeds of super-massive black holes and why they are so ubiquitous in galaxies.
The collaboration setup cosmological simulations that followed the evolution of dark matter and gas in the Universe as it collapses along the network of cosmic filaments. As gas moves along the filaments it reaches the most massive dark matter haloes present in the Universe, which sit at the crossing of filaments. In the present study, four filaments converge onto the dark matter halo under investigation and provide cold and dense gas streams that collide at the centre of the halo and form turbulent gaseous clouds. The ability of this gas to further collapse and form stars is severely suppressed by the presence of turbulence and only picks up once the mass of the clouds has increased to allow catastrophic collapse forming super-massive stars several ten thousand times the mass of the sun. The lifetime of super-massive stars is around a million years, after which they will collapse to form a black hole of similar mass, the seed of super-massive black holes that we see today.
Professor Khochfar commented:
This simulation is pointing the way to finally settle the 20-year-old question on the birth of super-massive black holes in the Universe. The beauty of the proposed black hole seeding channel is that it does not require any fine tuning and is a natural consequence of structure formation along the cosmic web in a Universe that consists of dark energy and dark matter.