Just as animals tend to rest and sleep for a long time after eating large quantities, black holes have the same behavior, as identified by the James Webb Space Telescope (JWST).
The most powerful observatory of NASA and ESA, managed to capture a gigantic black hole slumbering in the early universe. New research published in Nature demonstrated the discovery of a dormant supermassive black hole whose mass is 400 million times that of the Sun, that existed in the early universe, just 800 million years after the Big Bang.
The mass of this supermassive black hole caught the attention of researchers because represents about 40% of the mass of its host galaxy. In the local (and recent) universe, these cosmic titans typically have only 0.1% of the mass of their galaxies.
Scientists would expect such a gigantic black hole to feed voraciously and therefore grow. However, It is devouring gas at a very slow rate, about one hundredth of the maximum possible accretion limit for a celestial body of this size. This behavior makes it practically invisible. However, its enormous mass gave it away.
“Although this black hole is inactive, its enormous size allowed us to detect it. Its dormant state also allowed us to learn about the mass of the host galaxy. “The early universe managed to produce some absolute monsters, even in relatively small galaxies,” he explained. Ignas Juodžbalis, lead author of the study and member of the Kavli Institute of Cosmology in Cambridge.
Dormant black holes are difficult to identify because they lack the luminous accretion disk that normally surrounds active black holes.
Under normal conditions, gas and dust falling towards a black hole form this disk, which glows brightly due to the heat and friction generated in the process. However, in this case, the immense gravitational mass of the black hole allowed its detection, even without the characteristic glow.
Current models of black hole formation and growth explain that they originate from the collapse of massive stars and then grow slowly through the accumulation of matter, as gas and dust, until reaching its theoretical feeding limit, known as Límite de Eddington.
This limit establishes that a black hole cannot accumulate matter indefinitely, since the radiation generated by accretion exerts pressure that eventually expels nearby material.
However, the existence of this dormant black hole in the early universe suggests that these models do not tell the whole story. Thus, the discovery of such a massive black hole at an early stage of the universe challenges all known models of the cosmos.
“It is possible that black holes were born large, which could explain why Webb detected huge black holes in the early universe. But another possibility is that they go through periods of hyperactivity, followed by long periods of inactivity,” commented the professor. Roberto Maiolinoco-author of the study and researcher at the Kavli Institute.
To solve this mystery, the researchers performed computer simulations in collaboration with colleagues in Italy. These actions suggest that black holes can temporarily exceed the Eddington limit for short periods of time, a phenomenon known as super-Eddington accretion.
In this scenario, black holes would experience brief bursts of ultrafast growth that would last between 5 and 10 million years. During these episodes, they would consume matter at exponential rates, quickly reaching colossal sizes. Afterwards, they would enter long periods of inactivity that could last up to 100 million years.
“It seems contradictory to explain a dormant black hole with periods of hyperactivity, but these short bursts allow it to grow rapidly while it spends most of its time sleeping,” Maiolino added. This pattern of intermittent activity could explain How supermassive black holes reached their enormous dimensions in such a short time since the origin of the universe.
Maiolino and his colleagues explain that supermassive black holes are cosmic titans with masses equivalent to millions or even billions of suns. Unlike stellar-mass black holes, which form when massive stars collapse, these large objects are believed to grow through a chain of mergers of later more massive black holes and from a constant diet of gas and dust from their host galaxies.
And they estimate that this process takes more than a billion years to create a supermassive black hole with a mass even on the lowest scale of these monstrous masses. That means detecting a supermassive black hole in the recent history of our 13.8 billion year old cosmos It is not problematic.
The discovery not only provides evidence for these new theories, but also underlines how difficult it is to detect inactive black holes. The low luminosity of these objects during their dormant periods makes them almost invisible even to advanced telescopes like JWST.
“This was the first result I obtained as part of my PhD, and it took me a while to appreciate how extraordinary it was. It wasn’t until I started talking to my colleagues about the theoretical side of astronomy that I was able to see the true importance of this black hole”Juodžbalis reflected.
Researchers suspect that this black hole is just the tip of the iceberg. If most black holes in the early universe spent much of their existence in a dormant state, there could be a large number of them yet to be discovered. However, identifying these sleeping giants will remain a challenge due to their elusive nature.
He James Webb Space Telescope has revolutionized our understanding of the early universe since it began operating in 2022. This finding is an example of how its advanced technology can reveal previously invisible phenomena.
In addition, the study raises new questions about the role of black holes in the evolution of galaxies. While these massive objects are known to influence the dynamics of their host galaxies, the fact that one of them represents 40% of the total mass of its galaxy raises questions about the relationship between the two.
This discovery also has implications for future research. Astronomers will need to develop new techniques to detect inactive black holes and refine theoretical models of the formation and growth of these objects.
He Finding this dormant supermassive black hole marks an important step in understanding the early universe, but also remember how limited our current knowledge is. Maiolino concluded optimistically: “It is likely that the vast majority of black holes are in this dormant state. “I’m surprised we found this one, but I’m excited to think there are many more we could find.”
As the James Webb Telescope continues to explore the far reaches of the cosmos, we are likely to discover more examples of these sleeping giants, which could redefine what we know about the origin and evolution of black holes.
