This black hole is 400 million times the mass of the Sun, as seen with the state-of-the-art Webb Space Telescope. Webb can see the earliest light in the universe by observing light in the near and mid-infrared, which helps it penetrate clouds of interstellar dust and see fainter, more distant light sources. According to the team of astronomers who studied the black hole, it is essentially at rest despite its young age, which casts doubt on traditional models of black hole growth. The researchers published their findings today in the journal Nature.
“Despite the fact that this black hole is at rest, its enormous size allowed us to detect it,” said Ignace Juodjbalis, a researcher at the University of Cambridge’s Kavli Institute for Cosmology and lead author of the study, in a university press release. “Its state of quiescence also allowed us to learn about the mass of the parent galaxy. The early Universe managed to create some absolute monsters, even in relatively tiny galaxies.”
Black holes are believed to form from collapsed stars, and their intense gravitational fields accumulate matter around them. The matter swirling around the black hole glows and is called the accretion disk. Sometimes matter falls into the gaping mouth of the black hole, causing a bright flash of light – this is how the black hole is powered.
Black hole accretion disks are filled with tidbits for astronomers seeking to better understand how objects from which light cannot escape turn into some of the densest and most massive objects in space. In 2021, the team published a study on a star stuck in a loop with a black hole. In 2022, another team watched a black hole vomit up a star a few years after it ate it. This year, one team determined that the fastest-growing black hole swallows the Sun in a day, and another team accurately predicted the snacking schedule of a black hole 50 million times the mass of our Sun about 860 million light-years from Earth.
There are two fundamental differences between this snacking black hole and the one recently studied in the Webb data. First, the recently studied black hole is much, much larger and makes up about 40% of the total mass of its galaxy. And the crux of the problem: The newly studied black hole barely eats, which changes previous ideas about the evolution of black holes.
“It’s possible that black holes are ‘born big,’ which could explain why Webb spotted huge black holes in the early universe,” study co-author Roberto Maiolino, a researcher at the Kavli Institute and Cambridge’s Cavendish Laboratory, said in the same release. “But the other possibility is that they go through periods of hyperactivity followed by long periods of rest.”
The idea is that black holes rapidly accumulate material and briefly exceed their predicted size limit. The gravitational behemoths then relax and rest for about 100 million years before swallowing up even more space.
Black holes are challenging objects to study; in addition to their extreme physics, there is the obvious problem that they do not emit light. Fortunately, careful study of the shadows of objects and their effects on surrounding matter-including the accretion disk-allows astronomers to build better models that mimic some of the most extreme physical phenomena that space has to offer.
