Related papers: Modelling Giant Radio Halos
We investigate the possibility that radio halos of clusters of galaxies are caused by synchrotron emission of cosmic ray electrons (CRe), which were produced by cosmic ray protons (CRp) interacting hadronically with the intra-cluster medium…
We have performed 323 MHz observations with the Giant Metrewave Radio Telescope of the most promising candidates selected from the MACS catalog. The aim of the work is to extend our knowledge of the radio halo and relic populations to…
Aims. We present the first results of an ongoing project devoted to the search of giant radio halos in galaxy clusters located in the redshift range z=0.2--0.4. One of the main goals of our study is to measure the fraction of massive galaxy…
Detecting diffuse radio emission, such as from halos, in galaxy clusters is crucial for understanding large-scale structure formation in the universe. Traditional methods, which rely on X-ray and Sunyaev-Zeldovich (SZ) cluster…
We will discuss the properties and origins of halos and relics including estimates of the cluster magnetic fields, and present results for a few recently discovered halos and relics. The electrons in the suprathermal high energy tail of the…
Massive, merging galaxy clusters often host giant, diffuse radio sources that arise from shocks and turbulence; hence, radio observations can be useful for determining the merger state of a cluster. In preparation for a larger study, we…
The Fermi-LAT collaboration recently published deep upper limits to the gamma-ray emission of the Coma cluster, a cluster that hosts the prototype of giant radio halos. In this paper we extend previous studies and use a formalism that…
The existence and extent of non-thermal phenomena in galaxy clusters is now well established. A key question in our understanding of these phenomena is the origin of the relativistic electrons which may be constrained by the modelling of…
We use the GALFORM semi-analytical model to study high density regions traced by radio galaxies and quasars at high redshifts. We explore the impact that baryonic physics has upon the properties of galaxies in these environments.…
Clusters of galaxies, as the largest virialized systems in the Universe, are ideal laboratories to study the formation and evolution of cosmic structures...(abridged)... Most of the detailed knowledge of galaxy clusters has been obtained in…
Giant radio haloes are diffuse synchrotron sources typically found in merging galaxy clusters, while smaller mini-haloes occur in cool-core clusters. Both trace cosmic-ray electrons in the intracluster medium, though recent observations…
The interaction of magnetic turbulence and relativistic particles is a important process for understanding particles propagation and acceleration in many astrophysical environments. Large-scale turbulence can be generated in the…
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…
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…
We study the relation between radio halos, the energy input by supernovae in the disk and the galaxy mass. We find that both the energy input by supernovae as well as the galaxy mass are important parameters for understanding the formation…
Aims. The statistical properties of radio halos can be used to discriminate among the possible models for their origin. Therefore an unbiased and exhaustive investigation in this direction is crucial. Methods. With this goal in mind in this…
We developed a magneto-turbulent model for the cosmic ray (CR) electrons seen in the radio halo clusters of galaxies. Steady state momentum distribution functions of the CR electrons are calculated for given spectra of the turbulent Alfven…
We explore the shock acceleration model for giant radio relics, in which relativistic electrons are accelerated via diffusive shock acceleration (DSA) by merger-driven shocks in the outskirts of galaxy clusters. In addition to DSA,…
Galaxy clusters are considered to be gigantic reservoirs of cosmic rays (CRs). Some of the clusters are found with extended radio emission, which provides evidence for the existence of magnetic fields and CR electrons in the intra-cluster…
Some galaxy clusters show diffuse radio emission in the form of giant halos (GHs) on Mpc scales or minihalos (MHs) on smaller scales. Comparing VLA and XMM radial profiles of several such clusters, we find a universal linear correlation…