Related papers: The Case for Electron Re-Acceleration at Galaxy Cl…
Using our extensive radio, optical, near-IR and X-ray imaging and spectroscopy, we consider the reason for the unusually large number of radio detected galaxies, mostly found outside the cluster core, in Abell 2125 (z=0.2465, richness class…
Context. It is well-established that shock waves in the intracluster medium launched by galaxy cluster mergers can produce synchrotron emission, which is visible to us at radio frequencies as radio relics. However, the particle acceleration…
The hot plasma within merging galaxy clusters is predicted to be filled with shocks and turbulence that may convert part of their kinetic energy into relativistic electrons and magnetic fields generating synchrotron radiation. Analyzing Low…
Radio relics are sites of electron (re)acceleration in merging galaxy clusters but the mechanism of acceleration and the topology of the magnetic field in and near relics are yet to be understood. We are carrying out an observational…
In this paper we review the observational results on Relic radio sources in clusters of galaxies. We discuss their observational properties, structures and radio spectra. We will show that Relics can be divided according to their size,…
New multi-wavelength (radio, optical & X-rays) observational evidences are presented which show that the nearby (z=0.046), rich cluster of galaxies Abell 3376 is experiencing a major event of binary subcluster merger. The key evidence is…
Massive structures like cluster of galaxies, embedded in cosmic filaments, release enormous amount of energy through their interactions. These events are associated with production of Mpc-scale shocks and injection of considerable amount of…
Diffuse radio emission from galaxy clusters in the form of radio halos and relics are tracers of the shocks and turbulence in the intra-cluster medium. The imprints of the physical processes that govern their origin and evolution can be…
The presence of magnetic fields in the intra-cluster medium of galaxy clusters is now well estabilished. It is directly revealed by the presence of cluster-wide radio sources: radio halos and radio relics. In the last years increasing…
Radio relics are vast synchrotron sources that sit on the outskirts of merging galaxy clusters. In this work we model their formation using a Press-Schechter formalism to simulate merger rates, analytical models for the intracluster medium…
Radio relics are Mpc-scale diffuse radio sources at the peripheries of galaxy clusters which are thought to trace outgoing merger shocks. We present XMM-Newton and Suzaku observations of the galaxy cluster Abell 2744 (z=0.306), which reveal…
In the course of the formation of cosmological structures, large shock waves are generated in the intra-cluster medium. In analogy to processes in supernova remnants, these shock waves may generate a significant population of relativistic…
Non-thermal radio emission from cosmic ray electrons in the vicinity of merging galaxy clusters is an important tracer of cluster merger activity, and is the result of complex physical processes that involve magnetic fields, particle…
Galaxy-cluster merger shocks efficiently accelerate the ambient electrons through diffusive shock acceleration and amplify magnetic field by compressing the Inter Cluster Medium. As a result, such objects produce a significant amount of…
Radio observations discovered large scale non thermal sources in the central Mpc regions of dynamically disturbed galaxy clusters (radio halos). The morphological and spectral properties of these sources suggest that the emitting electrons…
We report evidence for enhanced quenching in low-redshift galaxy clusters hosting radio relics. This effect is strongest for low-mass galaxies and is consistent with a rapid quenching of star formation. These results imply that merger…
During their lifetime, galaxy clusters grow through the accretion of matter from the filaments of the large scale structure and from mergers with other clusters. These mergers release a large amount of energy into the intracluster medium…
Radio relics are arc-like synchrotron sources at the periphery of galaxy clusters, produced by cosmic-ray electrons in a $\mu$G magnetic field which are believed to have been (re-)accelerated by merger shock fronts. However, not all relics…
Galaxy clusters grow by a sequence of mergers with other clusters and galaxy groups. During these mergers, shocks and/or turbulence are created within the intracluster medium (ICM). In this process, particles could be accelerated to highly…
There is a growing evidence that extended radio halos are most likely generated by electrons reaccelerated via some kind of turbulence generated in the cluster volume during major mergers. It is well known that Alfv\'en waves channel most…