(ORDO NEWS) — Flashing like cosmic “beacons” 13 billion light-years from Earth, quasars are some of the oldest and brightest objects in the early universe ever recorded by astronomers.
Quasars (short for “quasi-stellar radio source”) are huge black holes whose neighborhoods glow so brightly that their luminosity is comparable to the luminosity of an entire galaxy.
The masses of the nuclei of quasars range from several million to several billion solar masses. In the modern universe, quasars can be found at the centers of many large galaxies.
But the exceptionally high luminosity of quasars also makes it possible to observe objects of this class located very far from us – for example, about 200 quasars were discovered in the early Universe, at an epoch when our world was no more than one billion years old.
How could such massive objects have formed so early in the history of the cosmos, when galaxies and large stars were extremely rare?
This question has been on the minds of scientists for more than two decades, and in a new study, a team led by Daniel Whalen of the University of Portsmouth, UK may have the answer.
Using computer simulations, the researchers recreated the formation of stars in the early universe, focusing on the rare instances when two streams of cold, turbulent gas collided.
Although in the modern Universe the flows of gas, which is the material for the formation of new stars, form a real “road network” with many intersections, in the first billion years after the Big Bang, in the early Universe, such natural “clouds” or reservoirs lying at the intersection of two gas streams were a rare phenomenon, which makes it difficult to study them with the help of observations.
In the constructed model, two large “clumps” of star-forming gas gradually formed at the intersection of these streams over millions of years. But to the team’s surprise, these clumps didn’t evolve into normal-sized stars, as previous models of the early universe suggested.
“These cold currents created turbulence in the gas cloud that prevented the formation of normal-sized stars until the cloud became so massive that it collapsed catastrophically under its own weight, forming two giant primary stars,” Whalen said. “The mass of the first star was 30,000 solar masses, and the second star was about 40,000 solar masses.”
According to previous estimates, the mass of a quasar at its birth is between 10,000 and 100,000 solar masses. If this is true, then both giant primary stars obtained in this simulation could become viable “embryos” of the first quasars in the Universe, the authors conclude.
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