Blazing up inside a dwarf galaxy in the early universe, the LID-568 black hole is consuming material about 40 times the theoretical limit, perhaps solving an old puzzle about how supermassive black holes reach maturity so quickly in cosmic time. Credit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani
For decades, astronomers have wondered how the supermassive black holes that reside at the centers of galaxies form. Now, researchers may have found the biggest clue yet as to how these monstrous objects, weighing millions of solar masses, came into existence.
An international team has used the high sensitivity of the James Webb Space Telescope (JWST) to investigate a group of galaxies previously studied by the Chandra X-ray Observatory’s COSMOS legacy Survey. In that data, they found a small (relatively speaking) supermassive black hole, called LID-568, that consumes matter faster than the theoretical limit allows. It exists just 1.5 billion years after the Big Bang, when galaxies were just reaching maturity on the cosmic scene.
Hungry, hungry black hole
The study, published earlier this month in Natural astronomy and led by astronomer Hyewon Suh of the Gemini International Observatory and the National Science Foundation’s NOIRLab, began by observing X-ray-bright galaxies that disappear into visible and near-infrared light. But LID-568’s X-ray emission was suspiciously stronger than the others, and they couldn’t pinpoint its exact location.
JWST’s spectroscopic instruments are capable of multiple observation modes. The most common is single-slit spectroscopy, which apparently aligns a long slit on the object of observation; light diffracts as it passes through the slit, producing a spectrum. But given the uncertain location of LID-568, this was not the best choice and the team did not want to waste observation time. Therefore JWST instrument scientists recommended using JWST’s Near InfraRed Spectrograph (NIRSpec) in its integral field spectrography mode. This mode uses multiple long slits to collect data from each pixel in the image. This allowed astronomers to obtain spectral data not only of the very faint target, but also of the even fainter surrounding area.
The observations revealed the black hole’s intense outflows of gas and allowed Suh’s team to calculate the speed and size of the gas. Their results indicate that LID-568 consumes matter more than 40 times faster than allowed by the theoretical limit – the so-called Eddington limit – and that a significant part of the system’s mass growth occurred during a single extremely high accretion event. quick. “This serendipitous result has added a new dimension to our understanding of the system and opened interesting avenues for investigation,” Suh said in the NOIRLab press release.
Race to greatness
When the science of black holes was still in its infancy, Sir Arthur Eddington mathematically found his way to the expression now called luminosity or the Eddington limit. It describes the maximum amount of brightness that an accreting system such as a black hole can have, when gravitational forces and outward radiation pressure are in balance. This brightness limit also defines the maximum rate at which black holes can accumulate matter. After all, black holes only appear bright when they are actively feeding, as the turbulent material falling into their throats heats up, glows, and sprays outward.
But in trying to explain the existence of supermassive black holes, astronomy has a problem. We see supermassive black holes not only in our local universe, but also quite far back in cosmic time, in times when there had been no Enough It’s about time a black hole got that big, at least not without exceeding the Eddington limit, a law astronomers thought they understood pretty well. How does a supermassive black hole become supermassive if its growth rate is limited and the universe has a finite age?
LID-568 could provide an answer as it is the first direct evidence of a black hole experiencing super-Eddington accretion. Suh said this finding “suggests that a significant portion of mass growth may occur during a single episode of rapid feeding.” in a press release.
Astronomers have already theorized about super-Eddington black holes. They would not be stable for long periods of time, but they could explain why supermassive black holes became so large and so quickly in the early stages of the universe.
“This black hole is celebrating,” astronomer and co-author Julia Scharwächter of the International Gemini Observatory/NSF NOIRLab said in a press release. “This extreme case shows that a fast-feeding mechanism above the Eddington limit is one possible explanation for why we see these very heavy black holes so early in the Universe.”
Perhaps, in the case of a black hole, rules like the Eddington limit are made to be broken.
