Related papers: Shocks and Nonthermal Processes in Clusters
We address the role of gamma-ray astronomy in the investigation of nonthermal processes in the large scale structure of the universe. Based on EGRET upper limits on nearby galaxy clusters (GCs) we constrain the acceleration efficiency of CR…
The main component of the intracluster medium (ICM) in clusters of galaxies is represented by the X-ray emitting thermal plasma. In addition, the presence of relativistic electrons and large-scale magnetic fields in a fraction of galaxy…
Some clusters of galaxies have been identified as powerful sources of non-thermal radiation, from the radio to X-ray wavelengths. The classical models proposed for the explanation of this radiation usually require large energy densities in…
Clusters of galaxies are the largest gravitationally bounded structures in the Universe dominated by dark matter. We review the observational appearance and physical models of plasma structures in clusters of galaxies. Bubbles of…
Clusters of galaxies are self-gravitating systems of mass ~10^14-10^15 Msun. They consist of dark matter (~80 %), hot diffuse intracluster plasma (< 20 %) and a small fraction of stars, dust, and cold gas, mostly locked in galaxies. In most…
Clusters of galaxies are the largest organized structures in the Universe. They are important cosmological probes, since they are large enough to contain a fair sample of the materials in the Universe, but small enough to have achieved…
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…
The high-density environment of galaxy clusters is ripe for collisional encounters of galaxies. While the large velocity dispersion of clusters was originally thought to preclude slow encounters, the infall of smaller groups into the…
Galaxy clusters are the most massive constituents of the large-scale structure of the Universe. While the hot thermal gas that pervades galaxy clusters is relatively well understood through observations with X-ray satellites, our…
Clusters of galaxies are the most massive objects in the Universe and precise knowledge of their mass structure is important to understand the history of structure formation and constrain still unknown types of dark contents of the…
We investigate the evolution of intracluster medium during a cluster merger, explicitly considering the relaxation process between the ions and electrons by N-body and hydrodynamical simulations. When two subclusters collide each other, a…
Massive galaxy clusters are the most violent large scale structures undergoing merger events in the Universe. Based upon their morphological properties in X-rays, they are classified as un-relaxed and relaxed clusters and often host (a…
Numerical simulations of cluster mergers reveal many characteristics of the merging process: shock structure and strength, observational signatures of the dynamical state, effects on the mass determination, turbulence and the evolution of…
We have developed a numerical model for the temporal evolution of particle and photon spectra resulting from nonthermal processes at the shock fronts formed in merging clusters of galaxies. Fermi acceleration is approximated by injecting…
Models for the integrated relativistic electron population in clusters of galaxies are presented. The results depend on the history of electron acceleration in the cluster. If there is no present particle acceleration or other sources, then…
Evolutions of X-ray clusters of galaxies are studied by N-body (shell model) + mesh code (TVD) simulations on the assumption of spherical symmetry. We consider a density perturbation of $10^{15} M_{\odot}$ composed of dark matter and gas in…
We compare the nonthermal emission from clusters of galaxies undergoing minor mergers (``accreting'' clusters) and major mergers (``merging'' clusters). For accreting clusters, the radial distribution of the nonthermal emission in the…
FERMI (formely GLAST) will shortly provide crucial information on relativistic particles in galaxy clusters. We discuss non-thermal emission in the context of general calculations in which relativistic particles (protons and secondary…
Within the standard framework of structure formation, where clusters and groups of galaxies are built up from the merging of smaller systems, the physical properties of the intracluster medium, such as the gas temperature and the total…
Groups and clusters contain a large fraction of hot gas which emits X-ray radiation. This gas yields information on the dynamical state and on the total mass of these systems. X-ray spectra show that heavy elements are present in the gas.…