Related papers: Radio Halos From Simulations And Hadronic Models I…
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…
Cooling flows are regions where the importance of non-thermal intra-cluster medium components such as magnetic fields and cosmic rays may be strongest within a galaxy cluster. They are also regions where such components are best detectable…
A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS)- an extension of the GMRT Radio Halo Survey…
The presence of non-thermal components in galaxy clusters is now clearly established. Diffuse radio emission from the Intra Cluster Medium (ICM) of several galaxy clusters is revealed in the form of radio halos and relics. These emissions…
The frequently observed association between giant radio halos and merging galaxy clusters has driven present theoretical models of non-thermal emission from galaxy clusters, which are based on the idea that the energy dissipated during…
The most important evidence of non-thermal phenomena in galaxy clusters comes from Giant Radio Halos (GRHs), synchrotron radio sources extended over Mpc scales, detected in a growing number of massive galaxy clusters. A promising…
In a growing number of galaxy clusters diffuse extended radio sources have been found. These sources are not directly associated with individual cluster galaxies. The radio emission reveal the presence of cosmic rays and magnetic fields in…
The intra-cluster medium of several galaxy clusters hosts large-scale regions of diffuse synchrotron radio emission, known as radio halos and relics, which demonstrate the presence of magnetic fields and relativistic electrons in clusters.…
The structure of the cosmic ray electron halo of a starburst galaxy depends strongly on the nature of galactic wind and the configuration of the magnetic field. We have investigated these dependencies by solving numerically the propagation…
A2319 is a massive, merging galaxy cluster with a previously detected radio halo that roughly follows the X-ray emitting gas. We present the results from recent observations of A2319 at 20 cm with the Jansky Very Large Array (VLA) and a…
Many galaxy clusters show diffuse cluster-scale emission in the form of radio halos, showing that magnetic fields and relativistic electrons are mixed in with the intra-cluster medium (ICM). There is general agreement that the origin of…
The Coma cluster of galaxies hosts the brightest radio halo known and has therefore been the target of numerous searches for associated inverse Compton (IC) emission, particularly at hard X-ray energies where the IC signal must eventually…
Radio bridges are diffuse synchrotron emission observed between merging galaxy clusters. Recent radio observations have reported both detections and non-detections of radio bridges between clusters. The detections imply the presence of…
The polarization data of the radio galaxy NGC4869, belonging to the Coma cluster and located in its central region, allow us to obtain information on the structure of magnetic field associated with the cluster itself. A magnetic field of…
Diffuse synchrotron radio emission has been observed in a number of cool-core clusters on scales comparable to that of the cooling region. These radio sources are called `mini-halos'. In order to understand their origin, which is still…
Giant radio halos are Mpc-size sources found in some merging galaxy clusters. The synchrotron emitting electrons are thought to be (re)accelerated by plasma turbulence induced by the merging of two massive clusters. Cool core galaxy…
We present low frequency observations at $315$ and $745$ MHz from the upgraded Giant Metrewave Radio Telescope (uGMRT) of the edge-on, nearby galaxy NGC $4631$. We compare the observed surface brightness profiles along the minor axis of the…
We present the first cosmological simulations of primordial magnetic fields derived from the constraints by the Cosmic Microwave Background observations, based on the fields' gravitational effect on cosmological perturbations. We evolved…
The number of diffuse radio halos in clusters of galaxies has grown in recent years, making it possible to derive statistical properties of these sources and of the hosting clusters. We show that diffuse sources are associated with X-ray…
Low-frequency radio observations are revealing an increasing number of diffuse synchrotron sources from galaxy clusters, dominantly in the form of radio halos or radio relics. The existence of this diffuse synchrotron emission indicates the…