This is how the first quasars were formed in the universe

July 6. () –

The mystery of how the first quasars were formed in the universe, something that has puzzled scientists for 20 years, has been resolved by astrophysicists who publish their finding in Nature.

The existence of more than 200 quasars powered by supermassive black holes less than a billion years after the Big Bang was still one of the pending problems in astrophysics because it was never fully understood how they formed so early.

The team of experts led by Dr. Daniel Whalen of the University of Portsmouth found that the first quasars formed naturally in the violent and turbulent conditions of rare gas reservoirs in the early universe.

Dr. Whalen, from the University’s Institute for Cosmology and Gravitation, said it’s a statement: “This discovery is particularly exciting because it has reversed 20 years of thinking about the origin of the first supermassive black holes in the universe.

“We find supermassive black holes at the centers of most massive galaxies today, which can be millions or billions of times the mass of the sun. But in 2003 we started finding quasars — highly luminous supermassive black holes that actively accumulate which are like cosmic lighthouses in the early universe) that existed less than a billion years after the Big Bang. And no one understood how they were formed in such early times.”

A few years ago, supercomputer simulations showed that the first quasars could form at the junctions of rare, cold and powerful gas streams. Only a dozen of these existed in a volume of space a billion light-years across, but the black hole had to have 100,000 solar masses at birth. Today, black holes form when massive stars run out of fuel and collapse, but they are usually only between 10 and 100 solar masses.

Astrophysicists had long theorized that between 10,000 and 100,000 solar-mass stars formed in the early universe, but only in exotic, finely tuned environments such as strong ultraviolet backgrounds or supersonic flows between gas and dark matter that were nothing alike. to the turbulent clouds in which the first stars originated, quasars formed.

Dr Whalen said: “We think of these stars as dinosaurs on Earth, they were huge and primitive. And they had short lives, living only a quarter of a million years before collapsing into black holes.

“Our supercomputer models go back to very early times and found that cold, dense gas streams capable of growing a billion-solar-mass black hole in just a few hundred million years created their own supermassive stars unnecessarily. of unusual environments.Cold currents caused turbulence in the cloud that prevented normal star formation until the cloud became so massive that it collapsed catastrophically under its own weight, forming two gigantic primordial stars, one with 30,000 solar masses and the other with 40,000.

“Consequently, the only primordial clouds that could form a quasar just after cosmic dawn, when the first stars in the universe formed, also conveniently created their own massive seeds. This simple and beautiful result not only explains the origin of the first quasars , but also their demographics: their number in the early days.

“The first supermassive black holes were simply a natural consequence of structure formation in cold dark matter cosmologies, children of the cosmic web.”