Related papers: Cosmic ray diffusion fronts in the Virgo cluster
The observed bimodality in radio luminosity in galaxy clusters is puzzling. We investigate the possibility that cosmic-ray (CR) streaming in the intra-cluster medium can 'switch off' hadronically induced radio and gamma-ray emission. For…
The fast rotating star CU Virginis is a magnetic chemically peculiar star with an oblique dipolar magnetic field. The continuum radio emission has been interpreted as gyrosyncrotron emission arising from a thin magnetospheric layer.…
Cosmic rays are thought to escape their sources streaming along the local magnetic field lines. We show that this phenomenon generally leads to the excitation of both resonant and non-resonant streaming instabilities. The self-generated…
We present detailed observations of MRC 0116+111, revealing a luminous, mini radio-halo of ~240 kpc diameter located at the centre of a cluster of galaxies at redshift z = 0.131. Our optical and multi-wavelength GMRT and VLA radio…
Low-frequency radio observations of galaxy clusters are the key to detecting the diffuse extended emission associated with them. The presence and properties of such radio sources in galaxy clusters reveal the existence of magnetic fields on…
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…
Observations of diffuse radio emission in galaxy clusters indicate that cosmic-ray electrons are accelerated on $\sim$Mpc scales. However, protons appear to be accelerated less efficiently since their associated hadronic $\gamma$-ray…
Diffuse, extended radio emission in galaxy clusters, commonly referred to as radio halos, indicate the presence of high energy cosmic ray (CR) electrons and cluster-wide magnetic fields. We can predict from theory the expected surface…
We describe three-dimensional magnetohydrodynamical modelling of powerful radio galaxies in realistic poor cluster environments. This modelling extends our earlier work on the hydrodynamics of radio galaxies as a function of their cluster…
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 on the detection of diffuse radio emission with peculiar morphology in the central region of the galaxy cluster Abell 2657. The most striking feature identified in our 144 MHz LOFAR image is a bifurcated radio arc that extends for…
Motivated by the discovery of the non-thermal Fermi bubble features both below and above the Galactic plane, we investigate a scenario in which these bubbles are formed through Galacto-centric outflow. Cosmic rays (CR) both diffusing and…
Diffusion of cosmic rays (CRs) is the key process of understanding their propagation and acceleration. We employ the description of spatial separation of magnetic field lines in MHD turbulence in Lazarian & Vishniac (1999) to quantify the…
Recent results on the radio emission from galaxy clusters are reviewed, with emphasis both on the radio galaxies and on the diffuse radio emission from the intracluster medium. We show that the formation of the tailed morphology in cluster…
We report the results from a 200 ks Chandra observation of the z=1.786 radio galaxy 3C294 and its cluster environment, increasing by tenfold our earlier observation. The diffuse emission, extending about 100 kpc around the nucleus, has a…
Cosmic ray propagation is diffusive because of pitch angle scattering by waves. We demonstrate that if the high-amplitude magnetohydrodynamic turbulence with $\tilde B/\langle B\rangle \sim 1$ is present on top of the mean field gradient,…
Radio observations of the magnetic chemically peculiar star CU Vir, carried out with the VLA in three different days, show that the radio emission at 20 cm is characterized by a strong enhancement at particular rotational phases. This radio…
Inverse Compton (IC) scattering of nuclear photons with relativistic electrons in the lobes of powerful radio galaxies and quasars can give detectable extended X-ray emission from the radio lobes if relativistic electrons with a Lorentz…
Radio continuum observations of external galaxies provide us with an excellent outside view on the distribution of cosmic-ray electrons in the disc and halo. In this review, we summarise the current state of what we have learned from…
As energetic particles diffuse out of radio and star-forming galaxies (SFGs), their intracluster density builds up to a level that could account for a substantial part or all the emission from a radio halo. We calculate the particle…