Using the James Webb Space Telescope (JWST), astronomers have seen a supermassive black hole in the “cosmic dawn” that appears to be extremely massive. The confusion comes from the fact that it doesn’t seem like this giant void was feeding on much surrounding matter during that time—but, to reach its incredible size, one would expect it to have been voracious when time began.
The supermassive black hole that powers a quasar at the heart of galaxy J1120+0641 was seen as it was when the universe was only about 5% of its current age. It also has a mass that is over a billion times that of the sun.
While it is relatively easy to explain how the closest, and thus most recent, supermassive black holes have grown to billions of solar masses, the merger and feeding processes that facilitate such growth are expected to take about a billion years. . This means that finding such supermassive black holes that existed before the 13.8-billion-year-old universe was a billion years old is a real dilemma.
Since it began operations in the summer of 2022, JWST has proven particularly efficient at detecting such challenging black holes in the cosmic dawn.
One theory surrounding the early growth of these voids is that they were involved in a feeding frenzy called “ultra-efficient feeding.” However, JWST observations of the supermassive black hole in J1120+0641 did not show any particularly efficient feeding mechanism on the material in its vicinity. This discovery casts doubt on the mechanism of supermassive growth of ultrafast feeding black holes and means that scientists may know even less about the early evolution of the cosmos than they realized.
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“Overall, the new observations only add to the mystery: early quasars were remarkably normal,” team leader and Max Planck Institute for Astronomy (MPIA) postdoctoral researcher Sarah Bosman said in a statement. “Regardless of which wavelengths we observe them at, quasars are nearly identical across all ages of the universe.”
Supermassive black holes control their diets
In the last 13.8 billion years of cosmic history, galaxies have grown in size by gaining mass or taking in surrounding gas and dust, cannibalizing smaller galaxies, or merging with larger galaxies.
About 20 years ago, before JWST and other telescopes began finding disturbing supermassive black holes in the early universe, astronomers had assumed that supermassive black holes in the hearts of galaxies grew gradually in accordance with the processes that led to the growth galactic.
In fact, there are limits to how fast a black hole can grow—limits that these cosmic titans help set themselves.
Due to the conservation of angular momentum, matter cannot fall directly into a black hole. Instead, a flattened cloud of matter called an accretion disk forms around the black hole. Further, the immense gravity of the central black hole creates powerful tidal forces that create turbulent conditions in the accretion disk, heating it and causing it to emit light across the electromagnetic spectrum. These emissions are so bright that they often outshine the combined light of every star in the surrounding galaxy. The regions in which all this happens are called quasars, and they represent some of the brightest celestial objects.
This glow also has another function. Despite having no mass, light exerts pressure. This means that the light emitted by quasars pushes the surrounding matter. The faster the black hole feeding the quasar, the greater the radiation pressure, and the more likely the black hole will cut off its food supply and stop growing. The point at which black holes, or any other accretors, starve to expel surrounding matter is known as the “Eddington limit”.
This means that supermassive black holes cannot feed and grow as fast as they want. Thus, finding supermassive black holes with masses as large as 10 billion Suns in the early cosmos, especially less than a billion years after the Big Bang, is a real problem.
Astronomers need to know more about early quasars to determine whether early supermassive black holes were able to overcome the Eddington limit and become so-called “super-Eddington accretors.”
To do this, in January 2023, the team focused JWST’s Mid-Infra Red Instrument (MIRI) on the quasar at the heart of J1120+0641, located 13 billion light-years away and seen as it was just 770 million years after the Big . noise The investigation constitutes the first infrared study of the middle of a quasar that existed in the cosmic dawn.
The spectrum of light from this early supermassive black hole revealed the properties of the large ring-shaped “torus” of gas and dust surrounding the accretion disk. This torus helps guide matter into the accretion disk, from where it is gradually fed into the supermassive black hole.
MIRI observations of this quasar showed that the cosmic supply chain functions similarly to that of “modern” quasars closer to Earth, which therefore exist at later ages of the universe. This is bad news for proponents of the theory that an improved feeding mechanism led to the rapid growth of early black holes.
Furthermore, measurements of the region around the supermassive black hole, where matter rotates at nearly the speed of light, conformed to observations of the same regions of modern quasars.
JWST observations of this quasar revealed a major difference between it and its modern counterparts. The dust in the torus around the accretion disk had a temperature of about 2,060 degrees Fahrenheit (1,130 degrees Celsius), which is about 100 degrees hotter than the rings of dust around supermassive black hole-powered quasars seen closer to Earth.
The research favors another method of early supermassive black hole growth that suggests these cosmic titans got a head start in the early universe, forming from “seeds” of black holes that were already massive. These heavy seeds would have had masses at least a hundred thousand times that of the Sun, having formed directly through the collapse of early, massive gas clouds.
The team’s research was published June 17 in the journal Nature Astronomy.
Originally posted on Space.com.