An international team of researchers has discovered the oldest black hole ever observed using the James Webb Telescope. Such an object dates back to 400 million years after the big bang, about 13 billion years ago.
Research resultswhich were published this Wednesday (January 17, 2024) in the magazine Naturethey are – according to Robert Maiolin, an astrophysicist from the University of Cambridge (UK), the institution that led the research – “a big step forward”.
Scientists believe that the existence of this surprisingly massive black hole – several million times larger than our Sun – so early in the universe confounds theories about the formation and growth of these objects.
What did the James Webb telescope discover?
Just two years ago, many mysteries of the universe remained hidden from astronomers, but the arrival of the James Webb Space Telescope, built by the US Space Agency (NASA), the European Space Agency (ESA) and the Canadian Space Agency (CSA), has changed things. This technological marvel opened a new era in astronomical research.
The telescope, which works in the infrared region, can see cold objects, very far away or hidden behind dust, allowing it to observe the early universe and see objects as old as the black hole it just discovered.
When the Hubble Space Telescope first detected the galaxy GN-z11 in 2016, it was the most distant galaxy scientists had ever identified. It was formed 13.4 billion years ago, just 400 million years after the big bang.
But although GN-z11’s record has since been broken, the galaxy remains something of an enigma. It was strangely luminous for such an old and compact galaxy. To be that bright, “it would take a large number of stars crammed into such a small volume,” Maiolino says in remarks reported by NPR. However, “given how young the universe was, it would have been difficult to create all those bright young stars in that relatively short period of time.”
Now in an article titled “A small and powerful black hole in the early universe,” published in Nature , Maiolino and his colleagues have an alternative explanation for all that light: a supermassive black hole with a mass about 1.6 million times that of our Sun. A black hole itself does not emit any light, but everything. Maiolino suggests that it could be hot and bright enough towards it to produce an intense galactic glow.
According to Maiolino, this is the oldest black hole ever discovered, and its mere existence calls into question where certain black holes come from and how they feed and grow.
An ancient and insatiable black hole
Scientists believe that this hole is so large that it must have formed in a different way: it could have been “born big,” or gobbled up matter at a rate five times greater than previously thought possible.
“Very primitive galaxies were extremely rich in gas, so they would be like a buffet for black holes,” the researcher suggests.
Like other black holes, this young black hole grows by eating material from its host galaxy, but it is much more voracious than other holes of later times.
A young host galaxy called GN-z11 shines with the presence of an enormously energetic hole at its center.
This galaxy is compact—about a hundred times smaller than the Milky Way—but astronomers believe the black hole is causing its death, or at least harming its development.
“This black hole basically eats (the equivalent of) the entire Sun every five years,” Maiolino says. “It’s actually much higher than we thought was feasible for these black holes.” Hence the word “vigorous” in the title of the article.
A new telescope full of possibilities
For the past twenty years, Maiolino has helped develop the James Webb Space Telescope, which will launch on Christmas Day 2021. Specifically, he is part of the team that designed and built one of its key instruments, the Near Infrared Spectrometer.
“The instrument (is) responsible for sorting the light from galaxies and stars (into) their colors,” he says. “So it’s basically a rainbow of a galaxy.
When Maiolino and his colleagues pointed the powerful new telescope and its instrument at the galaxy known as GN-z11, the details it returned were impressive.
“It was very exciting,” he recalls. “But at first we didn’t realize what he was telling us. The apparition was quite disturbing.” Maiolino and his team discovered what they were dealing with: a supermassive black hole parked at the center of the galaxy.
“Before Webb came online, I thought maybe the universe wasn’t that interesting when you went beyond what we could see with the Hubble Space Telescope. But that’s not the case at all: the universe has been quite generous in what we can see.” with the Hubble Space Telescope. that it shows us, and this is just the beginning,” he emphasizes.
Maiolino is confident that, thanks to its sensitivity, Webb will be able to find even older black holes in the coming months and years and dispel doubts about the origin of these objects.
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