The James Webb Space Telescope reveals that supermassive black holes were rarer in the early universe than expected
Using the James Webb Space Telescope (JWST), astronomers have discovered that when our 13.8-billion-year-old universe was between 4 billion and 6 billion years old, it had fewer feeding supermassive black holes than previously expected.
Such supermassive black holes, which can be millions or even billions of times as massive as the sun, grow by feeding on the matter that surrounds them in flat disks called accretion disks. The gravitational effects of these black holes also heat up that matter, thus emitting huge amounts of radiation. When a black hole participates in this extreme process, The entire area (including those radiation jets) is known as Active galactic nucleus, or AGN.
Although supermassive black holes exist in all large galaxies, not all of these massive gravitational objects consume enough matter to reach the AGN state. An AGN can emit so much light that it often outshines the combined light of every star in the galaxies in which it resides.
These results are provided by JWST medium infrared instrument (MIRI), provide insights into the properties of AGNs and emphasize the challenges associated with detecting these glasses in the early universe. Supported by Cosmic Evolution Early Release Science (CEERS) Program.The results also suggest that our universe may have been more stable than expected during its “teenage” years, which scientists speculated was the most intense period of star formation.
Related: How did supermassive black holes become so big so quickly right after the Big Bang?
The team came to their conclusions when they were studying a region of space called the Groth’s Ribbon, which lies near the Big Dipper between the constellations Ursa Major and Boötes. The region, which contains an estimated 50,000 galaxies, has been studied extensively, but not with a powerful telescope such as the James Webb Space Telescope.
“Our observations were taken this past June and December, and we aimed to characterize what galaxies looked like during the peak of star formation in the universe,” said Alison Kirkpatrick, team leader and assistant professor of astronomy and physics at the University of Kansas. he said in a statement. “This is a look back in time from 7 to 10 billion years into the past.”
Using MIRI, Kirkpatrick said she and her colleagues looked behind dust in galaxies that existed 10 billion years ago, which could be hiding cosmic phenomena such as the ongoing formation of stars and increasingly massive black holes.
“So, I did the first survey to look for these lurking supermassive black holes at the centers of these galaxies,” she added.
Early supermassive black hole galaxies offer a double surprise
This poll came as a surprise to Kirkpatrick and her colleagues. They expected the James Webb Space Telescope to find more AGNs than previous surveys of the same region, such as those with the Spitzer Space Telescope. Instead, only a few additional supermassive black holes feeding them have been detected.
“The results looked completely different from what I expected, which led to my first big surprise,” Kirkpatrick said. “One of the important discoveries was the rarity of rapidly growing supermassive black holes. This discovery raised questions about the whereabouts of these objects.”
She suggested that this means black holes could be growing at a slower rate than expected, and added that Spitzer may have miscalculated black hole feeding rates because the telescope allowed astronomers to spot only the brightest, most massive galaxies with fast-growing supermassive black holes.
They are known to put out more light than supermassive black holes, which feed at a slower rate, making them easier to detect.
The growth of supermassive black holes in the early universe is an important puzzle for astronomers to solve, because these cosmic giants are thought to influence their surroundings greatly. They can influence the growth of their host galaxies, for example, and moderate star formation, making them an important component of the overall evolution of the universe.
Kirkpatrick continued: “The results of the study indicate that these black holes do not grow rapidly, absorb limited material, and may not significantly affect their host galaxies.” “This discovery opens up a whole new perspective on the growth of black holes since our current understanding is largely based on the more massive black holes in the largest galaxies having large effects on their hosts, but it is likely that smaller black holes in these galaxies have a significant impact.” no.”
However, this wasn’t the only surprise these galaxies fell into the lap of Kirkpatrick and her team. The researchers were also surprised by the apparent lack of dust in the galaxies they studied.
“With the James Webb Space Telescope, we can identify much smaller galaxies than ever before, including those as big as the Milky Way or even smaller, which was previously impossible at these redshifts (cosmic distances),” Kirkpatrick said. “The most massive galaxies usually contain an abundance of dust due to their rapid star formation rates.”
And she continued: “I assumed that low-mass galaxies would also contain large amounts of dust, but they did not, which defies my expectations and provides another interesting discovery.”
This work could also have close implications for the slowly feeding, inactive supermassive black hole Sagittarius A* (Sgr A*), which lies at the center of the Milky Way.
Basically, the supermassive black hole in our galaxy is swallowing so little matter that if it were a human being, it would survive on a diet of one grain of rice every million years. But the team’s findings may imply that Dean A* may not always have been a conscientious eater.
They point out that the Milky Way may once have had active nuclei at its core.
“Our black hole appears to be quite calm, not showing much activity,” Kirkpatrick said. “One of the important questions about the Milky Way is whether it is active at all or has it gone through an AGN phase.” “If most galaxies, like our own, lack a detectable AGN, this could mean that our black hole was not more active in the past.
“Ultimately, this knowledge will help constrain and measure black hole masses, and shed light on the origins of black hole growth, which remain an unanswered question.”
The University of Kansas researcher was given more time with the James Webb Space Telescope to continue her study of the extended Groth Bar field using MIRI. This means that while this current research is focused on just 400 galaxies, future work will focus on up to 5,000 early galaxies.
The team’s research has been accepted for publication in The Astrophysical Journal, with a copy for post peer review available in the paper repository. arXiv.
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