An article published in the journal “Nature Astronomy”, one published in “The Astrophysical Journal Letters”, and one submitted for publication in “The Astrophysical Journal” report different aspects of the study of the most distant black hole detected at X-rays. Different teams of researchers combined data obtained with the Chandra X-ray Observatory and the James Webb Space Telescope to study the galaxy UHZ1 in X-ray and infrared light. The result is the discovery of a growing supermassive black hole approximately 470 million years after the Big Bang. The study offers evidence that it was born already having considerable mass, confirming that supermassive black holes grow from seeds that form from the direct collapse of enormous amounts of gas.
The image (X-ray: NASA/CXC/SAO/Ákos Bogdán; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare & K. Arcand) shows the galaxy UHZ1 as seen by the Chandra X-ray Observatory and the James Webb Space Telescope. UHZ1 is a really tiny object seen behind the Abell 2744 galaxy cluster.
Akos Bogdan of the Center for Astrophysics | Harvard & Smithsonian (CfA) led a team that found the supermassive black hole in the galaxy UHZ1 and published the results in “Nature Astronomy.” The James Webb Space Telescope determined that UHZ1 is approximately 13.2 billion light-years away. Two weeks of observations conducted with NASA’s Chandra X-ray Observatory showed X-ray emissions typical of a growing supermassive black hole.
Even these very powerful instruments were able to observe the UHZ1 galaxy thanks to a gravitational lens: the Abell 2744 galaxy cluster, about 3.5 billion light-years from Earth, distorted the image of UHZ1 with its force of gravity, magnifying it about four times. This allowed weak infrared and X-ray emissions to reach the Earth.
The estimate of the mass of the supermassive black hole at the center of the galaxy UHZ1 is very approximate, between 10 and 100 million times the Sun’s. The lower limit is still remarkable considering that it’s a very young galaxy. The X-ray emissions indicate that it’s growing dramatically by engulfing a lot of gas that heats up as it falls towards it to the point of generating those powerful electromagnetic emissions.
Observations from the James Webb Space Telescope also indicate that the galaxy UHZ1 is the result of a galaxy merger that occurred recently in astronomical terms. Galaxy mergers are still common today, and in the early universe, galaxies were full of hydrogen, a situation predicted to favor the formation of supermassive black hole seeds.
The collected data have a good correspondence with theoretical predictions regarding a black hole that was born with a mass between 10,000 and 100,000 times that of the Sun from the direct collapse of a giant cloud of gas. These predictions had already been proposed in 2017 for what was defined as an outsized black hole by Priyamvada Natarajan of Yale University, one of the members of Akos Bogdan’s team and the first author of the article submitted to “The Astrophysical Journal”.
The data collected by the James Webb Space Telescope is part of the Ultradeep Nirspec and nirCam ObserVations before the Epoch of Reionization (UNCOVER) survey. The article published in “The Astrophysical Journal Letters” is written by a team led by Andy Goulding of the UNCOVER team and describes UHZ1’s active galactic nucleus thanks to the spectroscopic data collected by the Near Infrared Spectrograph (NIRSpec).
This study offers new confirmations to models regarding the formation of primordial supermassive black holes and an example of the combined use of two very different instruments to achieve this result. This gives researchers the opportunity to continue the search for other active galactic nuclei that have characteristics that indicate a growth phase of their supermassive black hole.
