Quasars twinkle like cosmic beacons on a shore 13 billion light-years from Earth, and are among the oldest and brightest remnants of the early universe that astronomers can detect today.
Quasars, short for “quasi-stellar radio sources,” are giant black holes They glow as bright as galaxies and have a mass of millions to billions of times a landSun. Today, quasars are located at the centers of many large galaxies. But thanks to its extraordinary luminosity, quasars have been tracked at a great distance Spare timewith nearly 200 of them identified as having formed during the first billion years of our universe’s history.
How could such massive objects form so early, when galaxies were scattered and large stars exceptionally rare? The question has baffled researchers for more than two decades, ever since the first quasars were identified — and now, a new study is published July 6 in the journal. temper nature (Opens in a new tab)may provide a long-awaited answer.
Using computer simulations, the researchers modeled star formation in the early universe, focusing on one of the rare junctures where two streams of cold, turbulent gas met. While streams of star-forming gas crisscross the universe like cosmic highways today, the natural “clouds” or reservoirs where two streams met were extremely rare during the first billion years after the great explosionThis makes them alluring but elusive fields of study.
In the simulation, two large groups of star-forming gases gathered at the center of these currents over millions of years. But, to the team’s surprise, these clumps never coalesced to become full-size stars as previous models of the early universe had predicted.
“Cold currents caused a disturbance in the [gas] cloud that prevented normal stars from forming until the cloud became so massive it collapsed catastrophically under its own weight, forming two gigantic primordial stars,” study co-author Daniel Whalen, a senior lecturer in cosmology at the University of Portsmouth in England, said in to me statement (Opens in a new tab). “One [star] It was 30,000 solar masses and another 40,000 masses.”
Previous studies estimated that the quasar should measure between 10,000 and 100,000 solar masses at birth. If so, then both giant primordial stars from the new simulation could be viable “seeds” of the first quasars in the universe, the study authors wrote.
In fact, it is possible that both massive stars collapsed into black holes almost immediately and then continued to devour gas as they grew into supermassive quasars like those discovered by scientists in the early universe. As monstrous black holes continue to grow, the researchers write, they can merge, unleashing a torrent of spacetime ripples known as gravitational waves. It is likely that scientists will be able to detect these waves using special observatories in the coming decades, which could confirm the simulation results.
If confirmed, this research would overturn decades of thinking about star formation in the early universe. Previous studies have suggested that large primordial stars can only form in extreme environments where external forces, such as forces ultraviolet Radiation, it can prevent smaller stars from forming. This new simulation shows, however, that such exotic environments may not be necessary. Quasars seeds can naturally appear where rare streams of cold gas meet.
“The first supermassive black holes were simply a natural result of the formation of a structure in [the early universe] – children cosmic networkWallen said.
Originally published on Live Science.
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