A team of astronomers led by the University of Arizona has observed a light quasar 1
As well as being the most distant – and as an extension, the earliest – known quasar, the object is the first of its kind to show evidence of a leaking wind of superheated gas coming out of the vicinity of a black hole one-fifth the speed of light. In addition to the discovery of a strong wind driven by quasars, new observations also show intense star formation activity in the host galaxy, where the quasar, officially designated J0313-1806, is located.
Researchers will present their findings, which are accepted for publication in Astrophysical Journal Letters, during a press conference and scientific talk at the 237th meeting of the American Astronomical Society, which will be held in practice January 11-15.
The previous record among quasars in the children’s universe was discovered three years ago. The UArizona team also contributed to this discovery. Quasars are thought to be the result of supermassive black holes that absorb surrounding matter, such as gas or even entire stars, resulting in a vortex of overheated matter known as the accretion disk that revolves around the black hole. Due to the enormous energies involved, quasars are among the brightest sources in space, often overshadowing their host galaxies.
Although J0313-1806 is only 20 million light-years away from the previous record holder, the new quasar contains a supermassive black hole twice as heavy. This is a significant advance for cosmology, as it provides the strongest constraint on the formation of black holes in the early universe.
“This is the earliest evidence of how a supermassive black hole affects its host galaxy around it,” said the newspaper’s lead author, Fage Wang, a Hubble Fellow at the Steward Observatory in Arizona. “We know from observations of less distant galaxies that this must happen, but we have never seen this happen so early in the universe.”
Quasars, which have already accumulated millions, if not billions, of solar masses in their black holes when the universe was very young, pose a challenge to scientists trying to explain how they came into being when they barely had time to do so. . A common explanation for the formation of a black hole involves a star that explodes like a supernova at the end of its life and collapses into a black hole. When such black holes merge over time, they can – theoretically – grow into supermassive black holes. However, similar to what it would take many lives to build a pension fund by splitting the dollar each year, quasars in the early universe are a bit like little millionaires; they must have gained their mass in another way.
The newly discovered quasar provides a new benchmark, excluding two current models of how supermassive black holes form in such a short time. In the first model, massive stars, which consist mainly of hydrogen and lack most of the other elements that make up later stars, including metals, form the first generation of stars in a young galaxy and provide food for the nascent black hole. The second model includes dense star clusters that collapse into a massive black hole from the start.
However, the Quasar J0313-1806 boasts too massive a black hole to be explained by the aforementioned scenarios, according to the team that discovered it. The team estimates that if the black hole at its center formed another 100 million years after the Big Bang and grew as fast as possible, there would still need to be at least 10,000 solar masses to begin with.
“This tells you that whatever you do, the seed of this black hole must have formed by a different mechanism,” said co-author Xiaohui Fan, a regent professor and associate director of the Arizona Department of Astronomy. “In this case, the one that involves huge amounts of primary, cold hydrogen gas collapses directly into the seed black hole.”
Because this mechanism does not require full-fledged stars as a raw material, it is the only one that would allow the supermassive black hole of the quasar J0313-1806 to rise to 1.6 billion solar masses at such an early time in the universe. That’s what makes the new record quasar so valuable, Fenn explained.
“Once you move to lower redshifts, all models can explain the existence of these less distant and less massive quasars,” he said. “In order for the black hole to grow to the size we see with J0313-1806, it had to start with a germinal black hole of at least 10,000 solar masses, and that would only be possible in a direct collapse scenario. “
The newly discovered quasar seems to offer a rare glimpse into the life of a galaxy at the dawn of the universe, when many of the processes of galaxy formation that have since slowed down or stopped in galaxies that have existed for much longer were still in full swing. you are.
According to current models of galaxy evolution, supermassive black holes growing in their centers may be the main reason why galaxies eventually stop making new stars. Acting as a cosmic-sized lamp, quasars violently blow up their surroundings, effectively washing their host galaxy free of much of the cold gas that serves as the raw material from which stars form.
“We think these supermassive black holes are the reason why many large galaxies have stopped forming stars at some point,” Fenn said. “We are seeing this ‘suppression’ at lower redshifts, but so far we did not know how early this process began in the history of the universe. This quasar is the earliest evidence that hardening may have occurred at a very early age.”
By measuring the luminosity of the quasar, Wang’s team calculated that the supermassive black hole at its center absorbs the mass equivalent of an average of 25 suns each year, which is thought to be the main cause of its high-speed hot plasma wind blowing in a galaxy around it at relativistic speed. . By comparison, the black hole in the center of the Milky Way has become mostly dormant.
And while the Milky Way forms stars at a light rate of about one solar mass each year, J0313-1806 emits 200 solar masses over the same period of time.
“This is a relatively high rate of star formation, similar to that observed in other quasars of a similar age, and tells us that the host galaxy is growing very fast,” Wang said.
“These quasars are probably still in the process of building their supermassive black holes,” Fenn added. “Over time, the leakage of the quasar heats up and pushes all the gas out of the galaxy, and then the black hole has nothing to eat and will stop growing. This is evidence of how these earliest massive galaxies and their quasars grew.”
Researchers expect to find several more quasars from the same time period, including potential new record holders, said Ginny Ian, the second author of the report, who is a collaborator of Peter A. Stritmater at the Steward Observatory. Ian and Fan observed the Las Campanas Observatory in Chile at the Magellan Baade 6.5-meter telescope the night J0313-1806 was discovered.
“Our study of quasars covers a very wide field, which allows us to scan almost half of the sky,” Ian said. “We have selected more candidates for which we will continue with more detailed observations.”
Researchers hope to reveal more about the secrets of the quasar with future observations, especially with NASA’s James Webb Space Telescope, which is currently scheduled to launch in 2021.
“With ground-based telescopes, we can only see a point source,” Wang said. “Future observations could allow for a more detailed resolution of the quasar, to show the structure of its leakage and how far the wind extends in its galaxy, and that would give us a much better idea of its evolutionary stage.”
Galaxy is experiencing the feast of the black hole – for now
“The Outermost Quasar in the Universe,” Feige Wang, , January 12, 4: 10-4: 20 p.m. EST. aas.org/meetings/aas237
Luminous quasar at Redshift 7.642, arXiv: 2101.03179 [astro-ph.GA] arxiv.org/abs/2101.03179
Provided by the University of Arizona
Quote: The most remote open quasar sheds light on the growth of black holes (2021, January 12), extracted on January 12, 2021 from https://phys.org/news/2021-01-distant-quasar-black- holes.html
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