(ORDO NEWS) — In clusters of galaxies, there are some stars that go into intergalactic space, because they are pulled by the huge tidal forces that arise between the galaxies in the cluster.
The light emitted by these stars is called intracluster. Its brightness is less than 1% of the brightness of the darkest sky that we can observe from Earth.
This is one of the reasons why images taken from space are very valuable for its analysis.
Using the James Webb Space Telescope (JWST), IAC researchers Mireya Montes and Ignacio Trujillo were able to examine intracluster light from SMACS-J0723.3-7327 with an unprecedented level of detail.
In fact, JWST images from the center of this cluster are twice as deep as previous images taken by the Hubble Space Telescope.
To analyze this extremely weak “ghost” light, researchers have developed new methods of analysis. “In this work, we needed to do some additional JWST image processing to be able to study the intra-cluster light, since it is a weak and extended structure.
This was the key to avoiding errors in our measurements,” Mireia says.
Thanks to the data obtained, the researchers were able to demonstrate the potential of intracluster light to study and understand the processes that are involved in the formation of structures as massive as galaxy clusters.
“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 our own Milky Way,” she notes.
But these observations provide the key not only to understanding the formation of galaxy clusters, but also to the properties of the mysterious component of our Universe – dark matter.
Stars emitting intracluster light follow the gravitational field of the cluster, making this light an excellent indicator of the distribution of dark matter in these structures.
“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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