Scientists discover ancient black holes are breaking the universe’s ‘velocity limit’, casting doubt on multiple theories

Amazingly voracious black holes from the dawn of the universe break two big rules. Not only does it exceed the “rate limit” for black hole growth, it also produces extreme X-ray and radio emissions, two characteristics that are not predicted to coexist.

The object, a quasar known as ID830, is an extremely bright and active supermassive black hole (SMBH) that spews enormous amounts of radiation from its poles. It also emits powerful X-ray radiation, produced by falling material swirling around its dark mouth at nearly the speed of light.

ID830 is huge. About 12 billion years ago, when the Universe was about 15% of its current age, it already weighed 440 million solar masses. This makes it more than 100 times more massive than Sagittarius A*, the SMBH at the center of our Milky Way galaxy.

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Why is such a violation of the rules possible? In a paper published January 21 in The Astrophysical Journal, an international team of researchers observed ID830 at multiple wavelengths to find the answer.

Even black holes have their limits.

Black holes are the most voracious gluttons in the universe, but monsters also have feeding restrictions. As they attract gas and dust, this material accumulates in swirling accretion disks. Gravity pulls matter from the disk into the black hole, but the influx of matter creates radiation pressure that pushes it outward, preventing further inflow. As a result, the black hole becomes trapped by a self-regulating process called the Eddington limit.

However, black holes can temporarily bypass this limit and undergo a rapid growth spurt at the super-Eddington limit. Researchers have proposed multiple mechanisms for this cosmic gluttony. For example, “it should be entirely possible for a black hole to consume material faster than the Eddington limit in the short period before the radiation pressure increases to limit the accretion rate,” Anthony Taylor, an astronomer at the University of Texas at Austin who was not involved in the study, told Live Science in an email.

Alternatively, the black hole could consume material from the disk near its equator, while outward radiation pressure ejects material from the poles. “In this situation, the radiation pressure can exceed the Eddington limit because it does not directly resist the influx of material,” Taylor added. “There are a variety of geometries where this could work.”

Super-Eddington dynamics could help reconcile SMBH growth models with the expanding catalog of early Universe observations. The James Webb Space Telescope, with its outstanding infrared sensitivity, has revealed that the SMBH has defied all expectations and grown surprisingly quickly.

So why did the small business get fat so quickly? Some scientists suggest that the first and largest star in the history of the universe, a Population III star, collapsed, creating the “seed” for a black hole of more than 1,000 solar masses.

But even these giant seeds would require more than 650 million years of feeding at the Eddington limit to reach some of the observed sizes. This feat may seem impossible for several reasons, including the vast amounts of gas required to sustain mining for such long periods of time.

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Explosive growth of a black hole

The researchers calculated ID830’s growth rate by measuring its brightness at ultraviolet (UV) and X-ray wavelengths. The brightness of its X-rays suggests that ID830 is accreting about 13 times the Eddington limit’s mass, due to a sudden burst of incoming gas that may have occurred as ID830 shredded and swallowed objects that came too close.

“For an SMBH as heavy as ID830, this would require a heavier giant star or a huge gas cloud rather than a normal (main sequence) star,” study co-author Sakiko Obuchi, an observational astronomer at Waseda University in Tokyo, told Live Science in an email. Obuchi added that such a super-Eddington period could be incredibly short-lived, as “this transition period is expected to last about 300 years.”

ID830 also displays radio and X-ray emissions simultaneously. These two features are not expected to coexist, especially since super-Eddington accretion is thought to suppress such emissions. “This unexpected combination suggests a physical mechanism for extreme accretion and jet launches that is not yet fully captured by current models,” the researchers said in a statement.

So while ID830 fires massive radio jets, its X-ray emissions appear to come from a structure called the corona, produced when a powerful magnetic field from the accretion disk generates a thin but turbulent billion-degree cloud of turbocharged particles. These particles orbit at near the speed of light around a black hole, which NASA calls “one of the most extreme physical environments in the universe.”

Framework of early galaxy evolution

Taken together, ID830’s rule-breaking behavior suggests that ID830 is in a rare transition period of excessive consumption and excretion. This incredible feeding burst provides energy to both the jet and the corona, causing ID830 to shine brightly across multiple wavelengths while spewing out an excess of radiation.

Additionally, based on UV brightness analysis, quasars like ID830 may be unexpectedly common, the researchers said. Models predict that only about 10% of quasars have impressive radio jets, but these high-energy objects may be much more abundant in the early Universe than previously suggested.

Most importantly, ID830 shows how SMBH can control the growth of galaxies in the early universe. When a black hole swallows material at the super-Eddington limit, the energy from its ejection could heat the material and disperse it throughout the interstellar medium (gas between stars), suppressing star formation. As a result, ancient SMBHs like ID830 may have grown to giant size at the expense of their host galaxies.

in context

in context

brandon specter

Space and physics editor

“If super Eddington black holes are more common than we think, that probably means there are still major gaps in our understanding of how objects in the early universe formed. This discovery adds to the growing body of evidence from the James Webb Space Telescope that the stars, galaxies, and black holes of the ancient universe appear to be much larger and more mature than theory says.”