Scientists have figured out how the first quasars formed in the universe
(ORDO NEWS) — The mystery of how the first quasars in the universe formed – something that has puzzled scientists for almost 20 years – has now been solved by a team of astrophysicists.
The existence of more than 200 quasars powered by supermassive black holes less than a billion years after the Big Bang remained one of the unsolved problems in astrophysics, because it was not fully understood how they formed so early.
A team of experts led by Dr. Daniel Whalen of the University of Portsmouth has determined that the first quasars formed naturally in the brutal, turbulent conditions of rare reservoirs of gas in the early universe.
A few years ago, supercomputer simulations showed that early quasars could form at the junctions of rare, cold, powerful gas flows.
Today, black holes form when massive stars run out of fuel and collapse, but their mass is typically only 10-100 solar masses.
Astrophysicists have long assumed that stars between 10,000 and 100,000 solar masses formed in the early universe, but only under exotic, finely tuned conditions such as a strong ultraviolet background or supersonic flows between gas and dark matter that bear no resemblance to turbulent clouds in which the first quasars formed.
Dr. Whalen said: “To us, these stars are like dinosaurs on Earth, they were huge and primitive. And they had a short life span of only a quarter of a million years before decaying into black holes.”
Supercomputer models have gone back to the earliest times and found that cold, dense streams of gas capable of growing a billion-solar-mass black hole in just a few hundred million years have created their own supermassive stars without any need for an unusual environment.
The cold currents caused turbulence in the cloud that prevented the formation of normal stars until the cloud became so massive that it collapsed catastrophically under its own weight, forming two giant parent stars – one with a mass of 30,000 solar masses and the other with a mass of 40,000.
Hence, the only primordial clouds that could have formed a quasar just after the cosmic dawn – when the first stars in the universe were formed – also conveniently created their own massive seeds. This simple, beautiful result explains not only the origin of the first quasars, but also their demographics – their abundance in early times.
The first supermassive black holes were simply a natural consequence of the formation of structures in cold dark matter cosmologies – the children of the cosmic web.
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