(Cape Canaveral) Scientists have discovered the oldest black hole ever observed, a cosmic monster formed just 470 million years after the Big Bang.
The results, published Monday, confirm theories that supermassive black holes existed at the dawn of the universe. NASA’s James Webb Space Telescope and the Chandra X-ray Observatory have teamed up over the past year to make these observations.
Since the universe is 13.7 billion years old, the age of this black hole is therefore 13.2 billion years.
Even more surprising for scientists, this black hole is enormous: it is ten times bigger than the black hole in our Milky Way.
It is thought to weigh between 10% and 100% the mass of all the stars in its galaxy, said lead author Akos Bogdan of the Harvard-Smithsonian Center for Astrophysics. This figure is a far cry from the tiny proportion of black holes in our Milky Way and other nearby galaxies, estimated at 0.1%, he noted.
“It’s really very early in the universe to be such a behemoth,” said Priyamvada Natarajan of Yale University, who participated in the study published in the journal Nature Astronomy.
A complementary article was published in Astrophysical Journal Letters. “It’s amazing that this thing is already in place with its galaxy so early in the universe. »
Researchers believe the black hole formed from huge clouds of gas that collapsed into a galaxy next to another galaxy containing stars. The two galaxies merged and the black hole took over.
The fact that Chandra detected it using X-rays confirms “without a doubt that it is a black hole”, according to Mme Natarajan. With X-rays, “you actually capture the gas that is gravitationally attracted to the black hole, which accelerates and starts to glow in the X-rays,” she explained.
This quasar is considered a quasar since it is actively growing and the gas is blindingly bright, she added.
The Webb telescope alone may have spotted a black hole just 29 million years old, scientists say, but it has yet to be observed in X-rays and verified. Mme Natarajan expects other early black holes to be discovered, perhaps less far away, but still quite distant.
“We expect a new window to open in the universe, and I think this is the first crack,” she said.
The two space telescopes ― Webb and Chandra ·― used a technique called gravitational lensing to magnify the region of space where this galaxy, UHZ1, and its black hole are located. The telescopes used light from a much closer galaxy cluster, just 3.2 billion light years from Earth, to enlarge UHZ1 and its black hole much further into the background.
“It is a fairly faint object and, fortunately, nature enlarged it for us,” said M.me Natarajan.
Launched in 2021 at a distance of 1.6 million kilometers, Webb is the largest and most powerful astronomical observatory ever sent into space; he sees the universe in infrared. The much older Chandra Observatory sees X-rays; it was put into orbit in 1999.
“I find it absolutely incredible that Chandra can make such astonishing discoveries 24 years after its launch,” Bogdan said.