Science.- This is how the first quasars in the universe were formed – Publimetro México

Madrid, 6 (European Press)

The existence of more than 200 quasars powered by supermassive black holes less than a billion years after the Big Bang remained a prominent problem in astrophysics because how they formed so early was not fully understood.

The team of experts led by Dr Daniel Wallen 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 Wallen, from the university’s Institute of Cosmology and Gravitation, said in a statement: “This discovery is particularly exciting because it upended 20 years of thinking about the origins of the universe’s first supermassive black holes.

“We have found supermassive black holes in 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 – extremely bright supermassive black holes that are actively accreting like cosmic beacons in the early universe. ) that existed less than a billion years after the Big Bang. No one understood how they formed so early.”

A few years ago, supercomputer simulations showed that the first quasars could form at the intersections of rare, cold, and powerful gas streams. Only a dozen of these are found in the volume of space one billion light-years across, but the black hole must be 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 have long assumed 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 weren’t the same. From which the first stars arose, quasars were formed.

Dr. Wahl said: “We think of these stars as dinosaurs on Earth, they were huge and primitive. They have 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 find that cold, dense streams of gas capable of forming a billion-solar-mass black hole in just a few hundred million years created their supermassive stars unnecessarily. From 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 giant primordial stars, one of 30,000 solar masses and the other 40,000.

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

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