Napping after eating too much food is a dilemma many of us are lucky enough to face on Christmas Day. New research shows that billions of years ago, some early black holes also had to take a nap after overindulging.
use James Webb Space Telescope (JWST), astronomers discovered a dormant supermassive black hole Only 800 million years ago big Bang. The cosmic monster passed out after eating a particularly large meal of galactic gas and dust.
this black hole Remarkable due to its huge size. About 400 million times the mass sunwhich is the most massive black hole observed by JWST early universe. The findings were published on Wednesday (December 18) in the journal naturefurther complicating the mystery How supermassive black holes grew so huge so quickly In the early universe.
this The mass of this supermassive black hole Another reason it’s striking is that when these cosmic titans typically appear in the local (and nearest) universe, they weigh only about 0.1% of the mass of their host galaxy. The mass of this supermassive black hole is equivalent to about 40% of the mass of its host galaxy.
Scientists expect such a massive black hole to feed voraciously and grow as a result. However, this black hole is devouring gas at a very slow rate, about one percent of the maximum possible intake limit for a black hole of this size.
Because a black hole has something called “event horizon“Things that capture light (and other objects that pass through them) tend to be invisible if they are not greedily feeding and illuminating that substance.
when they are surrounded by material called flat clouds accretion disk The gravitational influence of supermassive black holes gradually feeds them, creating enormous friction that causes this cosmic reservoir to glow. This emission allows us to detect supermassive black holes.
However, this dormant supermassive black hole is different. This is because its huge mass gives it a huge gravitational influence, making it visible.
“Although this black hole is dormant, its enormous size allows us to detect it,” said team leader Ignas Juodžbalis from the Kaveri Institute of Cosmology in Cambridge. in a statement. “Its dormant state also allows us to understand the quality of the host galaxy.
“The early universe managed to produce some absolute monsters, even in relatively small galaxies.”
Why were early giant black holes a big problem?
Since JWST began observing the universe in 2022, this powerful instrument has discovered supermassive black holes from the early stages of the universe.
Supermassive black holes are cosmic giants with a mass equivalent to millions or even billions of suns. unlike stellar mass black holeSupermassive black holes are formed when massive stars collapse and are thought to grow through a subsequent series of mergers of more massive black holes and a steady diet of gas and dust from their host galaxies.
This process is thought to take more than a billion years to create a supermassive black hole with a mass even at the lower scales of these massive masses. This means finding a supermassive black hole in our recent history The universe 13.8 billion years ago No problem.
However, JWST discovered these cosmic titans when the universe was less than a billion years old, and sometimes as early as 600 million years later big Bangthere is a problem. The sheer size of this early black hole and the fact that it didn’t even grow rapidly by feeding make the problem even more puzzling.
“Black holes may be ‘born big,’ which could explain why JWST found huge black holes in the early universe,” said team member Roberto Maiolino, a Kavli researcher. “But another possibility is that they go through a period of hyperactivity, followed by a long period of dormancy.”
Black hole pushed to the limit of overfeeding
Maiolino and colleagues re-examined the problem of supermassive black holes in the early universe by simulating the growth mechanism of black holes. The most likely explanation, the team found, is that the black hole may briefly exceed its absorption limit.
This kind of feeding hat is called “Eddington limit” This suggests that any greedily accreting object will reach a point where the radiation it supplies will push matter away, cutting off its food supply.
The team believes that early black holes may have experienced massive overfeeding or “Super Eddington accretionDuring these periods, greedy black holes will grow at super accelerated rates.
“It sounds counterintuitive to explain a dormant black hole by a period of hyperactivity, but these brief bursts allow it to grow rapidly while spending most of its time dozing,” Maiolino said.
The dormant periods of these black holes are 10 to 20 times longer than Super-Eddington accretion periods, which means astronomers are more likely to catch these cosmic giants while taking a nap than at dinner.
The discovery of this giant nap black hole is a breakthrough in this theory.
This massive early black hole may be just the tip of the iceberg, and the team suspects the early universe may have been filled with these sleeping giants. Unfortunately, the dormant nature of these monsters will make it difficult for astronomers to spot them.
“It’s likely that the vast majority of black holes are in this dormant state – I’m surprised that we found this one, but I’m happy to think that we can find more,” Maiolino concluded.