The James Webb Telescope continues to study the paths opened by the Hubble Telescope with the goal of going beyond it. Latest discovery, the most distant known supermassive black hole, which is also the most distant known AGN.
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In 2015, the Hubble telescope broke its distance record for a galaxy by observing what was then called EGSY8p7 but has since been renamed CEERS_1019. AstronomersAstronomers observed it as it was about 570 million years ago. Photons emitted by this galaxy in the visible or ultraviolet have had their wavelength extended as they travel through the expanse of space before being caught by the Hubble mirror and then absorbed by its CCD sensors.
Part of the spectrum of CEERS_1019 has therefore been shifted towards red and more specifically towards infrared-infrared. The galaxy itself is sort of an example of the epoch of the observable cosmoscosm when what cosmologists call reionization and reionization took place. Emission of fossil radiation, about 380,000 after the Big Bang, had produced neutral atoms for the first time. But a few hundred million years later, ultraviolet radiation from the first stars and giant black holes that accumulated matter would largely re-ionize those atoms.
We still don’t know much about what happened during the reionization epoch, but we do know that our knowledge will take a giant leap with the James Webb telescope and its large mirror, which collects photons from distant, faint objects. Because of this, CEERS_1019 has received the most attention from researchers using the James-Webb.
This led to an article by a team led by astrophysicist Rebecca Larson from the University of Texas at Austin (USA), which is already available on arXiv and is awaiting publication in the Astrophysical Journal.
Jean-Pierre Luminet, research director at CNRS, and Françoise Combes, professor at the Collège de France, tell us about black holes and more specifically about supermassive black holes in galaxies and what lies behind AGNs (active galactic nuclei). © Hugot Foundation of the College de France
CEERS_1019, a laboratory to understand the origin of supermassive black holes?
It is now clear that CEERS_1019 already contained a supermassive black hole, a supermassive black hole about 10 million times the mass of our Sun, larger than the giant central black hole of our Milky Way, but that this black hole already transformed this galaxy into an AGN, an active nucleus , made of galactic active cores of galaxies, some of which are also known as quasars.
For researchers, CEERS_1019 actually contains the most distant supermassive black hole and AGN known to date.
Larson and his colleagues had been busy analyzing data collected by the JWSTJWST’s four instruments for an hour when they came to a surprising conclusion. Usually, the galaxies we observe have emissions that are dominant either related to the formation of young stars or due to the presence of an AGN. But in the case of CEERS_1019, both signatures were equally important, which was previously unknown.
AGNs with supermassive black holes much larger and barely older than CEERS_1019 were already known and are increasing. So it looks like the galaxy is actually a kind of missing link between the first feverishly star-forming galaxies and those with large supermassive black holes.
It is therefore possible that it contains traces of supermassive black hole formation that we do not yet understand. Should we include stars that are also supermassive at the onset of reionization, or simply a direct collapse of giant clouds of matter into a giant black hole, or yet another hypothesis? No one knows yet and the debate is still going on.