Data compiled by the James Webb Space Telescope (JWST) is helping answer many questions in astronomy but also raising new questions. Issues that we thought were simple become enigmas when we find data that does not agree with our preconceptions.
This is what happened to a team that was studying active galactic nuclei.
Less than we expected. The first galaxy surveys carried out by the JWST have left a surprisingly low number of active galactic nuclei (AGN), according to a study led by researchers from the University of Kansas.
Supermassive yes, but not so active. Galaxies have supermassive black holes (SMBH) at their centers. However, not all these black holes are the same. Astronomers distinguish them based on their activity. AGN are those that grow rapidly, swallowing a large amount of matter.
Theory tells us that young SMBH tend to fall into this category. After a period of activity, these black holes “deactivate” and become conventional supermassive black holes. This is what we believe happened to the black hole we found at the center of our own galaxy, the Milky Way.
Between 7,000 and 10,000 million years. Galactic surveys carried out by telescopes prior to JWST, such as Spitzer, allowed astronomers to find a number of active galactic nuclei in the galaxies around us. These were especially active, bright, and large nuclei, therefore easy to detect.
The team responsible for the new study believed that thanks to the greater power of the James Webb it would be possible to find many more nuclei of this type in deep space. Especially, they believed they would be able to find younger nuclei, still small but actively and rapidly growing.
They studied the region known as Groth’s Extended Band, a region located between the constellations Ursa Major and Boötes. The light from the galaxies located there and that now reaches us was emitted ago between 7,000 and 10,000 million years, Allison Kirkpatrick, co-author of the study, explained in a press release. The problem: The new survey didn’t reveal as many AGN as the team expected.
Our own history. The implications could even make us change our conception of the history of the Milky Way. Our galaxy is old and until now many considered it quite likely that it had an active nucleus at some point before “relaxing.”
If these results are confirmed, this hypothesis would become less likely. On the other hand, the possibility that our galaxy never had an active nucleus would gain points.
A new look. The JWST will have to continue working to solve this mystery. For now the team responsible for the work has published the details of research in the repository ArXivpending peer review and publication in a journal.
Meanwhile, they are preparing to once again access the tools of the most powerful space telescopes created by humanity. The JWST will have to continue searching to answer a question it itself has raised.
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Image | ESA/NASA/AVO/Paolo Padovani / NASA-GSFC, Adriana M. Gutierrez (CI Lab)
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