science

Most of the distant detected quasars shed light on how black holes grow

Most of the distant detected quasars shed light on how black holes grow

An international team of astronomers discovered the most distant quasar in the universe, which fully formed about 670 million years after the Big Bang. Credit: NOIRLab / NSF / AURA / J. da Silva

A team of astronomers led by the University of Arizona observed a luminous quasar 13.03 billion light-years from Earth – the most distant quasar ever discovered. Dating back to 670 million years after the Big Bang, when the universe was only 5% old, the quasar hosts a supermassive black hole equivalent to the combined mass of 1.6 billion suns.


In addition to being the most distant – and thus the closest – known quasar, this object is the first of its kind to show evidence of winds from extremely hot gas escaping from the periphery of the black hole at one-fifth of the speed of light. In addition to revealing strong winds propelled by the quasar, the new observations also show intense star-forming activity in the host galaxy where the quasar, officially named J0313-1806, is located.

Researchers will present their findings, which have been accepted for publication in The Astrophysical Journal Letters, During a press conference and scholarly conversation at the 237th meeting of the American Astronomical Society, which will take place roughly January 11-15.

The previous record among quasars was discovered in the infant universe three years ago. The UArizona team also contributed to this discovery. Quasars are thought to be caused by supermass black holes The surrounding matter, such as gas or even stars, is devoured entirely, causing a swirl of extremely hot matter known as the accretion disk orbiting the black hole. Because of the enormous energies involved, quasars are among the brightest sources in the universe, often outpacing the host galaxies.

Although J0313-1806 is 20 million light-years away from the previous record holder, the new quasar contains A supermassive black hole Poor weight This represents a major advance in cosmology, as it provides the strongest constraint yet on the formation of black holes in the early universe.

“This is the earliest evidence of how a supermassive black hole affected the host galaxy around it,” said lead author of the paper Vig Wang, Hubble fellow at the Steward Observatory of Arizona. “From observations of less distant galaxies, we know this should happen, but we didn’t see it happen very early in the universe.”

The quas stars have already collected millions, if not billions, from Solar masses In their black holes at a time when the universe was very small, it poses a challenge for scientists trying to explain how they appeared when they barely had time to do so. The generally accepted explanation for black hole formation includes the explosion of a supernova star at the end of its life and its collapse into a black hole. When such black holes merge over time, they could – in theory – grow into supermassive black holes. However, it’s much the same as building a pension fund by chopping a dollar each year requires many ages. Early universe They are a bit like children of millionaires; They must have gained their mass by other means.

The newly discovered quasar provides a new standard by excluding two current models of how supermassive black holes form in such short time periods. In the first form, Huge stars Largely composed of hydrogen and lacking most of the other elements that would later make up stars, including minerals, they form the first generation of stars in a young galaxy and provide food for an emerging black hole. The second model includes dense star clusters that collapse into a supermassive black hole from the start.

Most of the distant detected quasars shed light on how black holes grow

An international team of astronomers discovered the most distant quasar in the universe, which fully formed about 670 million years after the Big Bang. Credit: NOIRLab / NSF / AURA / J. da Silva

However, Quasar J0313-1806 houses a black hole so massive that it cannot be explained by the above scenarios, according to the team that discovered it. The team calculated that if a black hole formed at its center early on that dates back 100 million years after the Big Bang and grew as fast as it could, then it should still have at least 10,000 solar masses.

“This tells you that no matter what you do, the seed of this black hole should have formed by a different mechanism,” said co-author Xiaohui Fan, Regent Professor and co-chair of the UArizona Department of Astronomy. “In this case, one containing massive amounts of cold primordial hydrogen gas collapses directly into a seed black hole.”

Since this mechanism does not require full stars as raw material, it is the only one that allows the quasar supermassive black hole J0313-1806 to grow to 1.6 billion solar masses at such an early time in the universe. This is what makes the new standard quasar so valuable, Fan explained.

“Once we move to the lower redshifts, all models can explain the existence of these less distant, less massive quasars,” he said. “For a black hole to grow to the size that we see with J0313-1806, it must start with a black hole with a seed of at least 10,000 solar masses, and this would only be possible in a direct collapse scenario.”

The newly discovered quasar appears to offer a rare glimpse into galaxy life at the dawn of the universe when many of the galaxy-forming processes that have slowed or stopped since then in galaxies that have been around for a longer period were still in their prime. .

According to current models of galaxy evolution, supermassive black holes growing in their centers could be the main reason why galaxies eventually stop forming new stars. Quasars act like a blowtorch of cosmic dimensions, as their surroundings explode fiercely, effectively cleaning up their host galaxy of much of the cold gas that acts as the raw material for the stars.

“We think these supermassive black holes were the reason many large galaxies stopped forming stars at some point,” Fan said. We observe this “cooling” at low redshifts, but until now, we did not know when this process started so early in the history of the universe. This quasar is the first evidence that cooling may have been occurring very early.

By measuring the luminosity of the quasar, Wang’s team calculated that the supermassive black hole at its center swallows the equivalent of 25 suns each year, on average, which is believed to be the main cause of the high-speed hot plasma winds blowing into the galaxy around it at relative speed. For comparison, the black hole at the center of the Milky Way is now mostly sleeping.

This CosmoView episode 17 for the noirlab2102 press release: The oldest supermassive black hole and quasar in the universe. Credit: Photos and Videos: NOIRLab / NSF / AURA / J. Da Silva, ESO / M. Kornmesser, CTIO / D. Munizaga, International Gemini Observatory / Kwon O Chul. Music: Stellardrone – Comet Halley

And while the Milky Way is forming stars At an elegant pace of about one solar mass per year, J0313-1806 produces 200 solar masses in the same time period.

“This is a relatively high rate of star formation, similar to what has been observed in other quasars of similar age,” he tells us. The host galaxy “It is growing very fast,” said Wang.

“It is assumed that these quas stars are still building their supermassive black holes,” Fan added. “Over time, the outflow of the quasar heats up and pushes all the gas out of the galaxy, and then the black hole has nothing to eat anymore and it will stop growing. This is evidence of just how large these early objects are.” Galaxies Its quasars are growing. “

The researchers expect to find a handful of quasars from the same time period, including possible new record numbers, said Jenny Yang, second author of the report and a colleague of Peter A. Stratmatter at the Steward Observatory. Yang and Fan were observing in the 6.5-meter-high Magellan Paddy Telescope at Las Campanas Observatory in Chile the night of the J0313-1806 discovery.

“Our quasar survey covers a very wide field, which allows us to survey nearly half of the sky,” Yang said. “We have selected more candidates and will follow them with more detailed notes.”

Researchers hope to discover more about the quasar’s secrets through future observations, especially with NASA’s James Webb Space Telescope, which is currently slated to launch in 2021.

“Through ground-based telescopes, we can only see a point source,” Wang said. “Future observations could make it possible to solve the quasar in more detail, and show the structure of its flow and how far the wind extends into its galaxy, and this should give us a much better idea of ​​its evolutionary stage.”


The galaxy survives the black hole’s feast – for now


more information:
“The most distant quasar in the universe”, Vij Wang, [238]January. 12, 4: 10-4: 20 PM EST. aas.org/meetings/aas237

Luminous quasar in Redshift 7.642, arXiv: 2101.03179 [astro-ph.GA] arxiv.org/abs/2101.03179

Introduction of
University of Arizona

the quote: Most Distant Discovered Quasar Shedding Light on How Black Holes Grow (2021, Jan 12) Retrieved January 12, 2021 from https://phys.org/news/2021-01-distant-quasar-black-holes.html

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