UNITED KINGDOM: Dr. Daniel Whalen of Portsmouth university and his team of researchers have discovered that the first quasars spontaneously emerged amid the intense, turbulent conditions of ephemeral gas reservoirs in the early universe.
Astrophysicists have now found the answer to the nearly 20-year-old enigma of how the universe’s first quasar evolved; their findings have been published in Nature.
One of the mysteries in astronomy is how more than 200 quasars fueled by supermassive black holes originated less than a billion years after the Big Bang. This is because their formation was never fully understood.
It has been 20 years since the first supermassive black holes in the cosmos were thought to have formed, according to Dr. Whalen of the university’s Institute of Cosmology and Gravitation.
He also said, “Most big galaxies currently include supermassive black holes at their cores, which can have masses millions or billions of times greater than the sun. But in 2003, we started to discover quasars, which are supermassive black holes that are actively accreting and extremely bright. Quasars are like cosmic lighthouses in the early universe, appearing less than a billion years after the Big Bang. And nobody knew how they came to be at such a young age.”
According to supercomputer models from a few years back, early quasars could emerge at the intersections of rare, cold, and powerful gas streams. In an area of space a billion light-years big, there were only a dozen of these, but they had to be 100,000 solar masses when they were born. Currently, black holes only reach masses of 10 to 100 solar masses when big stars run out of fuel and collapse.
Long-held theories in astrophysics suggested that 10,000–100,000 solar-mass stars formed in the early universe, but only in rare, precisely calibrated environments, such as strong ultraviolet backgrounds or supersonic flows between gas and dark matter, which had nothing in common with the turbulent clouds in which the first quasars formed.
We compare these stars to the massive, prehistoric dinosaurs that once roamed the world, according to Dr. Whalen. They too, lived only a quarter of a million years before disintegrating into black holes.
“Our supercomputer simulations went back to the very beginning and found that the cold, dense streams of gas that could produce a billion solar-mass black holes in just a few hundred million years created their own supermassive stars without any need for peculiar circumstances.
Until the cloud became so large that it catastrophically collapsed under its own weight, the cold streams caused turbulence in the cloud that prevented regular stars from forming, giving rise to two enormous primordial stars, one of which was 30,000 solar masses and the other of which was 40,000.”
As a result, the only primordial clouds that were capable of producing quasars immediately following cosmic dawn, when the first stars in the universe were born, also by opportune coincidence, produced their own gigantic seeds. The formation of the first quasars as well as their early demographics—their numbers—are explained by this elegantly straightforward result.
The research article “The Turbulent Origins of the First Quasars” appears in Nature.
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