Composite image of galaxy cluster Abell 2255. Blue is X-ray data from ROSAT. These show hot gas between the galaxies. Yellow and purple are radio data from LOFAR. The purple glow is radio emission surrounding the entire cluster. The yellow streaks are fast-moving particles in the cluster’s magnetic fields. The background image was taken with the SSDS. The image is about 18 million by 18 million light-years across. From Earth, the image covers a region of sky the size of four full moons. Source: ROSAT/LOFAR/SDSS/Botteon, et al.
A Dutch-Italian-German team of astronomers has observed a huge flare of radio emissions around a cluster of thousands of galaxies. They combined data from thousands of LOFAR antennas aimed at an area the size of four full moons for 18 nights.
This is the first time astronomers have been able to record radio emissions from such a large area over such a long period of time and in such detail. They published their findings in the journal on Wednesday (November 2). scientific advances in the article “Magnetic Fields and Relativistic Electrons Fill Entire Galaxy Clusters.”
Astronomers studied Abell 2255, a cluster of thousands of galaxies about a billion light-years from Earth toward the constellation Draco. The new images are 25 times sharper and have 60 times less noise than images captured with a precursor to LOFAR. The team had to develop new techniques to process the large amount of data.
Galaxy clusters are the most densely “populated” regions of the universe. They consist of hundreds to thousands of galaxies. Between the galaxies there is rarefied gas composed of high-energy particles and magnetic fields. Little is known about the origin of this gas and the mutual influence of particles and magnetic fields.
turbulence and shaking
“Based on the new images and our calculations, we believe that the radio emission from Abell 2255 was generated during the formation of the cluster,” said research leader Andrea Botteon (University of Leiden, Netherlands and Università di Bologna / INAF, Italy). . He adds that it’s the first time astronomers have studied these processes very far from the cluster center.
“In our theory, we assume that the particles are accelerated by the enormous turbulence and vibrations that occur when the cluster is formed. These movements, in turn, can also amplify the magnetic fields.”
In the future, the researchers want to point the LOFAR telescopes and telescopes yet to be built, such as the Square Kilometer Array, to other galaxy clusters for longer periods of time. They also want to observe Abell 2255 more closely. By doing so, they hope to learn more about the so-called cosmic web that connects galaxy clusters.
More information:
Andrea Botteon et al, Magnetic fields and relativistic electrons fill the entire galaxy cluster, scientific advances (2022). DOI: 10.1126/sciadv.abq7623. www.science.org/doi/10.1126/sciadv.abq7623
Provided by the Netherlands Research School for Astronomy
Citation: LOFAR antennas reveal huge glow of radio emissions surrounding galaxy cluster (2022 November 2) retrieved November 2, 2022 from https://phys.org/news/2022-11-lofar-antennas-unveil- giant-radio.html
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