In recent years, many supermassive black holes (SMBHs) have been discovered in the early Universe, which should not have become so large by the time of observation. For them there is a purely physical limit on the rate of mass absorption, which they usually cannot exceed. It was all the more surprising to find a black hole whose rate of absorption of matter exceeded the theoretical limit by 40 times.
An artistic representation of an overeating black hole. Image source: NSF NOIRLab
The discovery was made by a group of astronomers from the USA (from the Gemini and NSF NOIRLab observatories). Using the space observatory named after. James Webb, they observed a number of galaxies in the early Universe following observations from the Chandra X-ray Observatory. These galaxies were dim optically but bright in X-rays, indicating black hole activity at their centers.
The galaxy LID-568 attracted the attention of scientists. The Webb spectrometer helped determine the exact location of this object. Galaxy LID-568 was found to be 1.5 billion years after the Big Bang. The assessments showed that at the center of the galaxy there is an active supermassive black hole with a mass of 7.2 million solar masses. This is a relatively small mass for an SSD. Something else surprised me. The so-called Eddington limit for this black hole was exceeded 40 times!
When matter falls on a black hole, it spins around it in a spiral. All black holes in the Universe rotate because they arose from rotating objects. At the same time, the black hole creates a rotation of space-time around itself, forcing everything falling on it to also rotate in a contracting spiral (the gravitational force also acts sideways in this area, and not just towards the center).
The force of gravity and friction, which are strongest closer to the black hole, heat the matter in the accretion disk until it glows in all ranges of electromagnetic radiation. This radiation creates pressure from within on the matter falling on the black hole and prevents it from falling onto the black hole above a certain speed. This threshold is the Eddington limit (in the general case, it is introduced for stars that keep their outer shells from falling onto the core), although this threshold can be exceeded for a relatively short time and then the super-Eddington effect appears when the accretion rate significantly exceeds the Eddington limit.
It appears that scientists stumbled upon LID-568 during a rare moment when it was consuming material at the super-Eddington limit. Therefore, further observations of this object can bring a lot of discoveries in the evolution of black holes. It has become a mystery to scientists how SMBHs in the early Universe were able to reach such large registered masses. This could have resulted from a situation where the first black holes arose directly from the collapse of clouds of matter or from incredibly huge first stars (neither one nor the other was observed).
Exceeding the Eddington limit may also provide an answer to the incredible fattening rate of SSD. The discovery of the LID-568 galaxy was a real find in this regard.