The James-Webb telescope continues to survey the paths opened by the Hubble telescope with the aim of going further than it. Latest discovery, the most distant known supermassive black hole, which is also the most distant known AGN.
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. Astronomers observed it as it was regarding 570 million years ago. The photons emitted by this galaxy in the visible or ultraviolet had their wavelength dilated by the expansion of space during their journey before being captured by the Hubble mirror, then being absorbed by its CCD sensors.
Part of the spectrum of CEERS_1019 was thus found shifted towards the red and more precisely towards the infrared. The galaxy itself is a sort of sample of the time in the observable cosmos where what cosmologists call reionization was happening. The emission of fossil radiation, around 380,000 following the Big Bang, had produced neutral atoms for the first time. But a few hundred million years later, the ultraviolet radiation from the first stars and giant black holes accreting matter would largely ionize these atoms once more.
We still don’t know much regarding what happened during the reionization epoch, but we know that with the James-Webb telescope and its large mirror collecting photons from distant and faint objects, our knowledge will do a giant leap. This is why CEERS_1019 has received all the attention of researchers using the James-Webb.
This resulted in an article from a team led by astrophysicist Rebecca Larson of the University of Texas at Austin (United States) and which can already be read on arXiv pending publication in The Astrophysical Journal.
Jean-Pierre Luminet, research director at the CNRS and Françoise Combes, professor at the Collège de France, tell us regarding black holes and in particular supermassive black holes in galaxies and which are 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 of regarding 10 million solar masses, more than the giant central black hole of our Milky Way, but that this black hole already made this galaxy an AGN, a nucleus active galaxies, some examples of which are also known as quasars.
For researchers, CEERS_1019 actually contains the most distant supermassive black hole and the most distant AGN known to date.
Larson and his colleagues were busy analyzing data collected for an hour by the JWST’s four instruments when they were faced with a startling conclusion. Usually, the galaxies that we observe have emissions that are dominant either in relation to the formation of young stars, or because of the presence of an AGN. But in the case of CEERS_1019, both signatures were equally important, unheard of until now.
AGNs with supermassive black holes much larger and hardly older than CEERS_1019 were already known, growing. So it looks like the galaxy is actually some sort 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 the origin of supermassive black holes that we still do not understand. Should we involve stars that are also supermassive at the beginning of reionization or simply a direct collapse of huge clouds of matter into a giant black hole, or yet another hypothesis? No one knows yet and the debate is still going on.
