Related papers: The Case for Electron Re-Acceleration at Galaxy Cl…
Radio relics in galaxy clusters are thought to be associated with powerful shock waves that accelerate particles via diffusive shock acceleration (DSA). Among the particles accelerated by DSA, relativistic protons should outnumber electrons…
Diffuse radio emission has been found in many galaxy clusters, predominantly in massive systems which are in the state of merging. The radio emission can usually be classified as relic or halo emission, which are believed to be related to…
Mergers between galaxy clusters often drive shocks into the intra cluster medium (ICM), the effects of which are sometimes visible via temperature and density jumps in the X-ray, and via radio emission from relativistic particles energized…
Radio galaxies in clusters of galaxies are prominent reservoirs of magnetic fields and of non-thermal particles, which get mixed with the intracluster medium. We review the observational and theoretical knowledge of the role of these…
Galaxy clusters grow by mergers with other clusters and galaxy groups. These mergers create shock waves within the intracluster medium (ICM) that can accelerate particles to extreme energies. In the presence of magnetic fields, relativistic…
The issue of radiation mechanisms had triggered in 1950-60s the first applications of plasma physics to understand the nature of radio galaxies. This interplay has steadily intensified during the past five decades, due to the premise of…
Some merging galaxy clusters host diffuse elongated radio sources, also called radio relics. It is proposed that these radio relics trace shock waves in the intracluster medium created during a cluster merger event. Within the shock waves…
Some merging galaxy clusters host diffuse extended radio emission, so-called radio halos and relics. Here we present observations between 147 MHz and 4.9 GHz of a new radio-selected galaxy cluster 1RXS J0603.3+4214 (z=0.225). The cluster is…
The recent evidences of the presence of magnetic fields and relativistic particles in galaxy clusters are reviewed. The existence of microG-level magnetic fields in cluster atmospheres appears well established from the detection of diffuse…
Radio halos and relics are diffuse radio sources found in galaxy clusters showing significant substructure at X-ray wavelengths. These sources provide important information about non-thermal processes taking place in the ICM. Until now only…
We report the discovery of a unique radio galaxy at z=0.137, which could possibly be the second spiral-host large radio galaxy and also the second triple-double episodic radio galaxy. The host galaxy shows signs of recent star formation in…
The origin of radio relics is usually explained via diffusive shock acceleration (DSA) or re-acceleration of electrons at/from merger shocks in galaxy clusters. The case of acceleration is challenged by the low predicted efficiency of…
Previously it has been recognized that radio halos in galaxy clusters are preferentially associated with merging systems as indicated by substructure in the X-ray images and temperature maps. Since, however, many clusters without radio…
Radio emission in the form of giant radio relics is observed at the periphery of galaxy clusters. This non-thermal emission is an important tracer for cosmic-ray electrons and intracluster magnetic fields. One striking observational feature…
Clusters of galaxies generally form by the gravitational merger of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. Mergers drive shocks into the intracluster gas, and…
In some clusters of galaxies, a diffuse non-thermal emission is present, not obviously associated with any individual galaxy. These sources have been identified as relics, mini-halos, and halos according to their properties and position…
Giant radio halos are Mpc-scale diffuse radio sources associated with the central regions of galaxy clusters. The most promising scenario to explain the origin of these sources is that of turbulent re-acceleration, in which MeV electrons…
The largest galaxy clusters are observed still to be forming through major cluster-cluster mergers, often showing observational signatures such as radio relics and giant radio haloes. Using LOFAR Two-meter Sky Survey data, we present new…
We present a first attempt to investigate the origin of radio-emitting electrons in the newly discovered class of mega radio halos in clusters of galaxies. We study the evolution of relativistic electrons accreted by the external regions of…
In this paper we investigate a situation where relativistic particles are reaccelerated diffusing across regions of reconnection and magnetic dynamo in super-Alfvenic, incompressible large-scale turbulence. We present an exploratory study…