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After the universe has been created, it took a few million years for the first light to shine through the cosmos. The first stars began to form, as did the ancient galaxies. As the gas and dust at the center of these galaxies began to wrap around their supermassive black holes, they formed the brightest objects in the entire universe – quasars.
Quasars give us a glimpse of what the universe looked like in its early days, and scientists are able to come back to these cosmic beasts through telescopic time travel.
A team of researchers recently announced the discovery of the most distant quasar on record, dating back 670 million years after the Big Bang. The quasar was accompanied by the oldest black hole ever observed. But the extreme age of this black hole isn’t its only notable feature – it’s absolutely (super) massive. And scientists can’t explain how it got to its extreme size, either.
The discovery was announced Tuesday at the 237th meeting of the American Astronomical Society, and is detailed in a study accepted for publication in the Astrophysical journal letters.
HERE IS THE HISTORY – Quasars were discovered in the 1960s. Their name is derived from the fact that they are “ quasi-stellar objects ” because a single quasar emits the same amount of light as a trillion stars, while occupying an area of space smaller than our solar system.
Scientists believe that quasars form when galaxies have copious amounts of gas and dust surrounding black holes in their centers, which eventually spiral and form an accretion disk of superheated material that swirls around.
Due to their high energy, quasars often outperform the galaxies that host them.
What’s up – Scientists research these ancient beasts, informing them of the conditions at the start of the universe and the formation and evolution of galaxies over time. What’s more, quasars can also help scientists better understand the relationship between galaxies and the black holes at their centers.
A team of scientists from the University of Arizona have been able to detect the most distant quasar ever observed, located 13.03 billion light years from Earth. This means that the quasar existed when the universe was only 670 million years old – only 5% of its current age (astronomers believe the universe is 13.8 billion years old).
The quasar, nicknamed J0313-1806, is over ten trillion times brighter than the Sun and has about a thousand times more energy than the entire Milky Way.
The quasar hosts a supermassive black hole at its center, with a mass of 1.6 billion suns. Compared to the supermassive black hole at the center of the Milky Way, which measures 13.67 million times the mass of the sun, he’s a pretty big boy.
Recent observations also show that the quasar has a flow of superheated gas flowing as a high-speed wind from around the black hole at one-fifth the speed of light, according to the study.
Here’s what we don’t know – Scientists don’t know how this supermassive black hole was able to form and grow to such a size so early in the universe. In other words, how did he have time to gobble up so much surrounding material to reach his massive size?
“The black holes created by the very first massive stars could not have grown this large in just a few hundred million years,” said Feige Wang, NASA Hubble researcher at the University of Arizona and author main of the new article.
Scientists believe that black holes form as a result of the death of a massive star, an explosive supernova, or by feeding on the first generation of stars that form inside a galaxy. They then continue to grow over time by swallowing the material around them.
The team behind the new study calculated that if the black hole had formed as early as 100 million years after the Big Bang and had grown as fast as possible, it would still be around 10,000 masses. solar power and not the 1.6 billion it currently boasts.
“This tells you that whatever you do, the seed of this black hole must have been formed by a different mechanism,” said Xiaohui Fan, associate head of the University of Arizona Department of Astronomy and co-author. of the study. A declaration.
“In this case, one that involves large amounts of primordial, cold hydrogen gas collapsing directly into a black seed hole.”
Besides being too large for its own good, the black hole also ingests the mass equivalent of 25 suns each year. Scientists believe that supermassive black holes of this size in the early universe are the main reason ancient galaxies stopped forming stars, with their black holes gobbling up all the gas and other materials necessary for the birth of baby stars.
AND AFTER – The rather turbulent relationship between black holes and their host galaxies in the early universe gives scientists a rare opportunity to study how galaxies formed and evolved over time, and the effects of their supermassive black holes on them. growth.
Researchers hope to conduct further observations of this quasar, as well as find more of these quasars in the early universe, following the launch of NASA’s James Webb telescope, currently scheduled for October 31, 2021.
Abstract: Distant quasars are unique tracers for studying the formation of the first supermassive black holes (SMBHs) and the history of cosmic reionization. Despite considerable effort, only two quasars were found at z ≥ 7.5, due to a combination of their low spatial density and the high contamination rate in the selection of quasars. We report the discovery of a luminous quasar at z = 7.642, J0313−1806, the most distant quasar still known. This quasar has a bolometric brightness of 3.6 × 1013L⊙. Deep spectroscopic observations reveal an SMBH with a mass of (1.6 ± 0.4) × 109M⊙ in this quasar. The existence of such a massive SMBH barely ∼670 million years after the Big Bang significantly challenges the theoretical models of SMBH growth. In addition, the quasar spectrum has strong characteristics of absorption lines (BAL) in CIV and SiIV, with a maximum speed close to 20% of the speed of light. The relativistic characteristics of BAL, combined with a strongly blue-shifted CIV emission line, indicate that there is a strong outflow from the active galactic nucleus (AGN) in this system. ALMA observations detect the dust continuum and [CII] emission from the host galaxy of the quasar, giving an accurate redshift of 7.6423 ± 0.0013 and suggesting that the quasar is hosted by an intensely star-forming galaxy, with a star-forming rate of ∼ 200 M⊙ year – 1 and a dust mass of ∼7 × 107 M⊙. Follow-up observations of this reionization-era BAL quasar will provide a powerful probe into the effects of AGN feedback on the growth of the first massive galaxies.
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