A cluster of galaxies hides more than the type of bodies for which it receives its name. We also find planets, stars, and other celestial objects ejected from their galaxies into interstellar space by the intense gravitational pull in these regions of the universe. Today, the James Webb has visualized inside these clusters a mysterious type of light called “intracluster light”, and could reveal many secrets of dark matter and the evolution of the universe.
The intracumular lumen is extremely diffuse. Its origin is traced to those orphan galaxy stars. They float in the middle of the galaxy clusters without being gravitationally bound to any of them. Its light is so dim that it is too difficult to capture it from Earth. This is the reason why it has been a unique opportunity for the James Webb when it comes to revealing certain secrets of space.
The Instituto de Astrofísica de Canarias (IAC) has been in charge of leading the research. Thanks to this, they have obtained new clues about the formation processes of galaxy clusters, and even more importantly, about the behavior of dark matter. The study has been published in the journal The Astrophysical Journal Letters.
Mireia Montes and Ignacio Trujillo are the researchers who managed to explore the intracluster light of the cluster SMACS 0723. The capture boasts an unprecedented amount of detailand it is twice as deep as others captured with Hubble.
“This work highlights the processing that has been done to be able to study the intracumular lumen, a weak and extended structure, and that is totally necessary to avoid biases in our measurements.”
Mireia Montes, researcher at the IAC and author of the article
The potential of James Webb to observe the faintest lights in the universe
Thanks to the technology included in James Webb, the capture of intracluster light would not only serve to improve the understanding of dark matter. In addition, this ability to perceive such dim lights also would allow us to observe the universe at deeper levels. Let’s remember that as light travels and expands through space, it becomes dimmer. Thanks to James Webb, it would be much easier to explore these cases in greater detail.
“In this study we show the great potential of James Webb to observe such a faint object. This will allow us to study galaxy clusters that are much further away, and in much more detail.”
Mireia Montes, researcher at the IAC
But how can the intracumular lumen help us in the study of the mysterious dark matter?
It is known that the universe is 23% dark matter; a number far greater than that of baryonic or ordinary matter. Galaxies and their clusters are largely ordered by this invisible matter, and stars that emit intracluster light follow the gravitational pattern of the cluster. In this way, researchers could track the distribution of dark matter in these structures just by looking at the movement of intergalactic stars.
Ignacio Trujillo, second author of the article, confirms this. He claims that “The James Webb will allow us to characterize the distribution of dark matter on these enormous structures with unprecedented precision and shed light on their basic nature.”