An international team of researchers led by Leiden University (the Netherlands) has mapped nine gigantic collisions of galaxy clusters. The collisions took place seven billion years ago and could be observed because they accelerate particles to high speeds. It is the first time that collisions of such distant clusters have been studied. The researchers publish their findings in the journal Nature Astronomy on Monday evening 2 November.
Source:
https://phys.org/news/2020-11-astronomers-gigantic-collisions-galaxy-clusters.html