Reviewed by Lexie CornerNov 5 2024
A team of astronomers from the U.S. National Science Foundation NOIRLab has discovered a supermassive black hole at the center of a galaxy that formed just 1.5 billion years after the Big Bang. Using data from NASA’s James Webb Space Telescope (JWST) and the Chandra X-ray Observatory, this black hole is consuming matter at an astonishing rate—over 40 times the theoretical limit. These findings were published in Nature Astronomy.
Artist concept of JWST. Image Credit: NOIRLab
Most galaxies contain supermassive black holes at their cores, which remain visible to modern telescopes even at surprisingly early stages of the universe’s development. However, understanding how these black holes were able to grow so rapidly poses a significant challenge.
Recent discoveries provide important insights into the mechanisms of quickly expanding black holes in the early universe, particularly following the identification of a low-mass supermassive black hole observed just 1.5 billion years after the Big Bang, which is consuming material at an extraordinary rate.
A multi-institutional team of astronomers, led by Hyewon Suh from the International Gemini Observatory/NSF NOIRLab, discovered LID-568. They studied a sample of galaxies from the COSMOS legacy survey conducted by the Chandra X-ray Observatory using the JWST.
While this population of galaxies is not visible in the optical and near-infrared regions of the spectrum, it is extremely bright in the X-ray range. JWST’s exceptional infrared sensitivity allows it to detect these faint counterpart emissions.
Although LID-568’s strong X-ray emissions made it prominent in the sample, its exact location could not be determined from the X-ray observations alone, complicating the task of centering the target within JWST's field of view.
To address this, scientists supporting JWST's instrumentation recommended that Suh’s team utilize the integral field spectrograph on JWST’s NIRSpec, rather than conventional slit spectroscopy. This instrument enables the collection of a spectrum for every pixel in its field of view, rather than being limited to a small slice.
Owing to its faint nature, the detection of LID-568 would be impossible without JWST. Using the integral field spectrograph was innovative and necessary for getting our observation.
Emanuele Farina, Study Co-Author and Astronomer, International Gemini Observatory/NSF NOIRLab
The team obtained a comprehensive view of their target and the surrounding area using JWST’s NIRSpec, leading to the surprising discovery of strong gas outflows surrounding the central black hole. They concluded that a significant portion of LID-568’s mass growth likely occurred during a single episode of rapid accretion, as indicated by the size and speed of these outflows.
This serendipitous result added a new dimension to our understanding of the system and opened up exciting avenues for investigation.
Hyewon Suh, Astronomer, International Gemini Observatory/NSF NOIRLab
Suh and her colleagues also found that LID-568 appears to be consuming matter at a rate 40 times faster than its Eddington limit. This limit defines the maximum luminosity and matter absorption rate that a black hole can sustain to balance its inward gravitational pull with the outward pressure created by the heat of the infalling matter.
The team realized they had something extraordinary in their data when they calculated that LID-568's luminosity was significantly higher than what was theoretically possible.
This black hole is having a feast. This extreme case shows that a fast-feeding mechanism above the Eddington limit is one of the possible explanations for why we see these very heavy black holes so early in the Universe.
Julia Scharwächter, Study Co-Author and Astronomer, International Gemini Observatory/NSF NOIRLab
These findings provide new insights into how smaller black hole “seeds” — believed to form from the direct collapse of gas clouds (heavy seeds) or the deaths of the Universe’s first stars (light seeds) — give rise to supermassive black holes. Until now, there has been no observational evidence supporting these theories.
Suh added, “The discovery of a super-Eddington accreting black hole suggests that a significant portion of mass growth can occur during a single episode of rapid feeding, regardless of whether the black hole originated from a light or heavy seed.”
The discovery of LID-568 also demonstrates that a black hole can exceed its Eddington limit, providing astronomers with a unique opportunity to explore the mechanisms behind this phenomenon. The powerful outflows observed in LID-568 may act as a release valve for the excess energy generated by the extreme accretion, helping to stabilize the system. To investigate these mechanisms further, the team plans to conduct additional observations with JWST.
Journal Reference:
Suh, H. et. al. (2024) A super-Eddington-accreting black hole ~1.5 Gyr after the Big Bang observed with JWST. Nature Astronomy. doi.org/10.1038/s41550-024-02402-9