JWST found black holes that shouldn’t exist this early, then researchers discovered a surprising explanation

Some of the unusually massive black holes discovered by the James Webb Space Telescope (JWST) in the early universe may have been misidentified as cosmic giants. A new study suggests that smaller black holes growing at extreme rates could produce signals that make them appear far more massive than they really are.

Since the beginning of JWST observations, astronomers have detected black holes located at the centers of galaxies that existed within the first billion years of the universe. These objects are identified through the radiation released when surrounding material falls toward them and heats up.

The mass of a black hole is usually estimated by measuring the speed of gas orbiting around it. Faster-moving gas indicates stronger gravity, which points to a more massive object. This method has been used successfully for decades, but early telescope observations produced unexpected results, with some black holes appearing much larger relative to their host galaxies than those observed in the nearby universe.

Another mystery added to the challenge: many of these distant black holes are almost invisible in X-rays. Active black holes generally produce X-ray radiation from a region of extremely hot plasma called the corona, positioned above the rotating accretion disk. The absence of this emission raised questions about whether these objects were truly as massive as initial estimates suggested.

A New Model Challenges The Size Of Early Black Holes

A team led byAlessandro Trinca at the INAF Astronomical Observatory of Rome investigated whether the apparent contradiction could be explained by the way these black holes consume matter. The study, published in Astronomy & Astrophysics on June 19, presents a model combining super-Eddington accretion physics with detailed simulations of accretion disk spectra.

Super-Eddington accretion occurs when a black hole feeds faster than the theoretical limit at which radiation from the object should prevent additional gas from falling inward. In such conditions, the intense flow of material can modify the radiation produced by the system.

The researchers proposed that this process could explain both the weak X-ray signals and the unusually high mass estimates. The emission lines used to measure the movement of gas around the cosmic giant may be altered, causing astronomers to overestimate the object’s true mass.

The team applied the model to 14 X-ray-silent black holes previously studied using standard techniques. The results offered two possible interpretations for each source.

Small Black Holes Can Appear Much Bigger

The first scenario described truly massive black holes that were almost inactive. In this case, the objects would contain large amounts of mass but would consume very little surrounding gas, limiting their radiation output.

The second scenario involved smaller ones experiencing intense periods of super-Eddington growth. This explanation naturally accounts for the lack of strong X-ray emissions because extreme feeding conditions can suppress the formation of the hot corona responsible for producing X-rays.

The statistical comparison between the two possibilities strongly favored the second scenario for almostall 14 objects. The researchers wrote in their study that super-Eddington accreting systems could produce an intrinsically red spectrum, matching other observed properties of these sources.

This result provides a possible solution to one of the major questions surrounding early black hole evolution. If these objects are smaller but rapidly feeding, they would not require the same level of extremely fast growth previously needed to explain their apparent masses.

The Next Observations May Hold the Answer

The researchers also pointed out that their model does not include every possible explanation for the missing X-ray emissions. The study does not account for extremely dense gas clouds that could block X-rays before they reach telescopes. The authors noted that:

Future studies using detailed spectral measurements across multiple wavelengths will help provide more accurate estimates of black hole masses and feeding rates. These observations will allow astronomers to better understand the nature of the distant objects detected by JWST.