Speaker
Description
The majority of baryonic matter in the Universe resides as plasma within the large-scale cosmic web, with galaxy clusters representing its densest nodes. These clusters grow through accretion and mergers, processes that inject substantial energy into the intracluster medium via shocks and turbulence. Low-frequency radio observations have revealed that these mechanisms accelerate particles to relativistic energies, producing diffuse synchrotron emission. LOFAR has been pivotal in advancing our understanding of this non-thermal emission, uncovering steep-spectrum, megaparsec-scale radio structures in clusters. Studies of radio relics link these arc-like features to merger-driven shock waves, while radio halos are associated with turbulence and evolving cluster dynamics. Mini-halos, typically found in relaxed clusters, have also been observed to extend well beyond central cores. In addition, LOFAR has revealed new phenomena such as ultra-steep spectrum emission, diffuse radio bridges in pre-merging systems, and large-scale radio envelopes surrounding clusters, highlighting the widespread presence of cosmic rays and magnetic fields. This talk will provide an overview of LOFAR’s key contributions to the study of non-thermal processes in galaxy clusters and outlines prospects for future work.
