A radio ridge connecting two galaxy clusters in a filament of the cosmic web.

["Govoni, F", "Orr\u00f9, E", "Bonafede, A", "Iacobelli, M", "Paladino, R", "Vazza, F", "Murgia, M", "Vacca, V", "Giovannini, G", "Feretti, L", "Loi, F", "Bernardi, G", "Ferrari, C", "Pizzo, R F", "Gheller, C", "Manti, S", "Br\u00fcggen, M", "Brunetti, G", "Cassano, R", "de Gasperin, F", "En\u00dflin, T A", "Hoeft, M", "Horellou, C", "Junklewitz, H", "R\u00f6ttgering, H J A", "Scaife, A M M", "Shimwell, T W", "van Weeren, R J", "Wise, M"]

Science (New York, N.Y.) 2019

Open on PubMed

Galaxy clusters are the most massive gravitationally bound structures in the Universe. They grow by accreting smaller structures in a merging process that produces shocks and turbulence in the intracluster gas. We observed a ridge of radio emission connecting the merging galaxy clusters Abell 0399 and Abell 0401 with the Low-Frequency Array (LOFAR) telescope network at 140 megahertz. This emission requires a population of relativistic electrons and a magnetic field located in a filament between the two galaxy clusters. We performed simulations to show that a volume-filling distribution of weak shocks may reaccelerate a preexisting population of relativistic particles, producing emission at radio wavelengths that illuminates the magnetic ridge.