With JWST, astronomers discovered the oldest black hole in the universe, challenging existing theories about the growth of the black hole and its potential impact on the development of its host galaxy GN-z11. Researchers have discovered the oldest black hole ever observed, dating back to the beginning of the universe, and found that it “eats” its host galaxy until it dies.

An international team led by the University of Cambridge has discovered a black hole dating back 400 million years after the Big Bang, more than 13 billion years ago, using the James Webb Space Telescope (JWST). The results, which lead author Professor Roberto Maiolino said were “a giant step forward”, were published in the journal today (January 17). Nature.

Challenging existing theories

The fact that this surprisingly massive black hole, with a mass several million times that of our Sun, existed so early in the universe challenges our assumptions about how black holes form and grow. Astronomers believe that supermassive black holes at the center of galaxies such as the Milky Way reached their current size over billions of years. But the size of this newly discovered black hole suggests they could form in other ways, too: They could “rise large” or absorb matter five times faster than possible.

Formation of supermassive black holes

According to standard models, supermassive black holes can form by collapsing the remains of dead stars, creating a black hole with a mass approximately one hundred times the mass of the Sun. If it had grown as expected, it would have taken about a billion years for this newly discovered black hole to reach its observed size. However, when this black hole was discovered, the universe was not yet a billion years old.

“It’s too early to see such a massive black hole in the universe, so we have to look at other ways of their formation,” said Maiolino, of Cambridge’s Cavendish Laboratory and Kavli Institute of Cosmology. “Very early galaxies were extremely rich in gas, so they were like a buffet for black holes.”

Like all black holes, this young black hole sucks material from its galaxy to fuel its growth. However, it was discovered that this ancient black hole absorbed matter much more strongly than its counterparts from later ages.

The effect of a black hole on a galaxy

The young host galaxy, called GN-z11, shines from such an energetic black hole at its center. Black holes cannot be observed directly, but instead are detected by light from a rotating accretion disk that forms near the edges of the black hole. The gas in the accretion disk becomes extremely hot and begins to glow and emit energy in the ultraviolet range. Thanks to this strong glow, astronomers can detect black holes.

GN-z11 is a compact galaxy about a hundred times smaller than the Milky Way, but the black hole is likely to be disruptive to its development. When black holes consume too much gas, they push the gas like a super-fast wind. This “wind” could stop the star formation process, slowly killing the galaxy, but it would also kill the black hole itself, as it would cut off the black hole’s “food” source.

New era in astronomy

Maiolino says JWST’s breakthrough was the most exciting time of his career. “This is a new era: a giant leap in sensitivity, especially in the infrared, like going from a Galileo telescope to a modern telescope overnight,” he said. “Before Webb came online, I thought the universe wasn’t as interesting as what we can see with the Hubble Space Telescope. But that’s not the case at all: The universe has been pretty generous with what it shows us, and this is just the beginning.”

Maiolino says JWST’s sensitivity means even older black holes may be found in the coming months and years. Maiolino and his team hope to use future observations of JWST to try to find smaller “seeds” of black holes; This could help them unravel the different ways black holes can form: whether they start big or grow quickly.