LOFAR antennae reveal the giant glow of radio emission surrounding the cluster of galaxies

A team of Dutch, Italian-German astronomers observed a huge radio emission glow around a cluster of thousands of galaxies. They combined data from thousands of LOFAR antennas that were focused for 18 nights over an area the size of four full moons.

This is the first time that astronomers have been able to capture radio emissions from such a large area for such a long time and in such detail. They published their findings on Wednesday November 2 in the journal Scientists progress in the article “Magnetic fields and relativistic electrons fill the entire galaxy cluster.”

Astronomers have studied Abell 2255. It’s a cluster of thousands of galaxies about a billion light-years from Earth in the direction of the constellation Draco. The new images are 25 times sharper and have 60 times less noise than images taken with a precursor to LOFAR. The team had to develop new techniques to process the large volume of data.

Galaxy clusters are the most “populated” regions of the universe. They consist of hundreds to thousands of galaxies. Between the galaxies there is rarefied gas of high energy particles and magnetic fields. Little is known about the origin of this gas and how particles and magnetic fields influence each other.

Turbulence and shocks

“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 director Andrea Botteon (University of Leiden, Country -Bas and Università di Bologna / INAF, Italy) . He adds that this is the first time that astronomers have studied these processes very far from the center of the cluster.

“In our theory, we assume that the particles are accelerated by the enormous turbulence and shocks produced during the formation of the cluster. In turn, these movements can also amplify the magnetic fields.”

In the future, researchers want to target LOFAR telescopes and buildable telescopes such as the Square Kilometer Array for longer periods at other galaxy clusters. Additionally, they intend to observe Abell 2255 in more detail. By doing so, they hope to learn more about the so-called cosmic web that interconnects clusters of galaxies.