An international team of researchers led by Leiden University (Netherlands) has mapped nine giant collisions of clusters of galaxies. The collisions took place seven billion years ago and are observable because they accelerate particles to high speeds. This is the first time that collisions of such distant clusters have been studied. The researchers published their findings in the journal Natural Astronomy on Monday evening 2/11.
Clusters of galaxies are the largest structures in the Universe. They may include thousands of galaxies, each with billions of stars. When such clusters merge, the electrons between them are accelerated to almost the speed of light. The accelerated particles emit radio waves when they are exposed to a magnetic field in clusters.
Until now, the telescopes were not strong enough to receive radio waves from distant collisions. But thanks to the Netherlands-Europe linked LOFAR antenna network and the ‘exposure time’ of 8 hours per cluster, researchers can gather detailed data from distant clusters for the first time. .
The data showed that, among other things, radio emissions from distant collision clusters were brighter than previously expected. According to popular theories, cluster radio emissions originate from electrons accelerated by turbulent movements. Study lead Gabriella Di Gennaro, Ph.D. Leiden University candidate (Netherlands) adds, “Hence, we think that the turbulence and vortex caused by the collision are strong enough to accelerate the particles also in a young Universe.”
Furthermore, the magnetic fields in the distal clusters turned out to be just as strong as in the nearby clusters that had been investigated previously. According to co-author and magnetic expert Gianfranco Brunetti (INAF-Bologna, Italy), this is surprising: “We still don’t know how these magnetic fields could be so strong in a still universe. Very young, but our research does present important limitations to their origins. We hope that future observations of distant clusters will provide more detailed information. ”
Nice mess in Abell 2255
Rapid magnetic field amplification in distant galaxy clusters, Natural Astronomy (Year 2020). DOI: 10.1038 / s41550-020-01244-5, www.nature.com/articles/s41550-020-01244-5
Provided by the Dutch School of Astronomical Studies
Quote: Astronomers see giant collisions of clusters in the young universe (2020, Nov. 2) retrieved November 2, 2020 from https://phys.org/news /2020-11-astronomers-gigantic-collisions-galaxy-clusters.html
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