(ORDO NEWS) — James Webb (JWST) has captured intracluster light (ICL), a very faint radiation produced by stars when these cosmic islands interact within a cluster.
The observation of this light is of great importance not only for understanding the evolution of galaxies and clusters of galaxies, but also for unraveling a mystery that is crucial to our entire understanding of the cosmos.
The resulting image SMACS-J0723.3-7327 was the first scientific observation published by the space observatory. Its sharpness is incredible and twice as deep as what we can see with the Hubble telescope.
Given that JWST sees the Universe in infrared light, the observations allow us to study galaxies that are much further away.
As the universe expands, the light from distant galaxies is “stretched” and shifted towards redder wavelengths, similar to the Doppler shift we can hear, for example, from a passing ambulance, where the pitch changes whether it is approaching or moving away from you. you.
“In this study, we show the great potential of JWST to observe such a faint object,” said first author Mireia Montes of the Canary Islands Institute of Astrophysics.
“This will allow us to study clusters of galaxies that are much further away and in much more detail.”
This light is still very faint, and the galaxies in the cluster are extremely bright, so observations alone cannot solve the problem.
It also requires methods to analyze the observations in such a way that the radiation can be isolated from the brighter sources in the image. The data obtained paints a picture of how a cluster of galaxies develops.
“By analyzing this scattered light, we find that the inner parts of the cluster are formed by the merger of massive galaxies, while the outer parts are due to the accretion of galaxies similar to the Milky Way,” explained Montes.
But the evolution of galaxies is not the only decisive factor here.
Our best understanding of the universe requires the presence of an invisible (and still hypothetical) substance known as dark matter, which only interacts gravitationally so it doesn’t accumulate and extends around galaxies.
In a cluster of galaxies with hundreds, if not thousands of galaxies, dark matter is spreading throughout and around the cluster, and ICL is the way to track it.
“The JWST will allow us to characterize the distribution of dark matter in these huge structures with unprecedented precision and shed light on its underlying nature,” concludes Ignacio Trujillo, second author of the paper.
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