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The existence of microgauss magnetic fields in galaxy clusters have been established through observations of synchrotron radiation and Faraday rotation. They are conjectured to be generated via small-scale dynamo by turbulent flow motions…

High Energy Astrophysical Phenomena · Physics 2020-01-15 Soonyoung Roh , Dongsu Ryu , Hyesung Kang , Seungwoo Ha , Hanbyul Jang

The recent evidences of the presence of magnetic fields and relativistic particles in galaxy clusters are reviewed. The existence of microG-level magnetic fields in cluster atmospheres appears well established from the detection of diffuse…

Astrophysics · Physics 2017-08-23 Luigina Feretti

Diffuse radio emission in galaxy clusters is a tracer of ultra-relativistic particles and $\mu$G-level magnetic fields, and is thought to be triggered by cluster merger events. In the distant Universe (i.e. $z>0.6$), such sources have been…

Faraday rotation and synchrotron emission from extragalactic radio sources give evidence for the presence of magnetic fields extending over ~Mpc scales. However, the origin of these fields remains elusive. With new high-resolution grid…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 F. Vazza , G. Brunetti , M. Brüggen , A. Bonafede

We investigate the evolution of magnetic fields in galaxy clusters starting from constant primordial fields using highly resolved ($\approx \rm 4 ~kpc$) cosmological MHD simulations. The magnetic fields in our sample exhibit amplification…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Paola Domínguez-Fernández , Franco Vazza , Marcus Brüggen , Gianfranco Brunetti

Giant radio halos in galaxy clusters probe mechanisms of particle acceleration connected with cluster merger events. Shocks and turbulence are driven in the inter-galactic-medium (IGM) during clusters mergers and may have a deep impact on…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 G. Brunetti

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…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-05 G. Brunetti , R. Cassano

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…

Recent radio observations with Low-Frequency Array (LOFAR) discovered diffuse emission extending beyond the scale of classical radio halos. The presence of such mega halos indicates that the amplification of the magnetic field and…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Kosuke Nishiwaki , Gianfranco Brunetti , Franco Vazza , Claudio Gheller

Observations of Faraday rotation and synchrotron emission in galaxy clusters imply large-scale magnetic fields with $\mu\mathrm{G}$ strengths possibly extending back to $z=4$. Non-radiative cosmological simulations of galaxy clusters show a…

Results are presented of a new VLA-ROSAT study that probes the magnetic field strength and distribution over a sample of 16 ``normal'' low redshift (z < 0.1) galaxy clusters. The clusters span two orders of magnitude in X-ray luminosity,…

Astrophysics · Physics 2009-10-31 T. E. Clarke , P. P. Kronberg , H. Boehringer

Faraday rotation of radio source polarization provides a measure of the integrated magnetic field along the observational lines of sight. We compare a new, large sample of Faraday rotation measures (RMs) of polarized extragalactic sources…

Astrophysics · Physics 2009-11-13 Yongzhong Xu , Philipp P. Kronberg , Salman Habib , Quentin W. Dufton

Diffuse radio sources in galaxy clusters are unique signposts of cluster assembly in the Universe. Our knowledge of their observational properties has considerably improved over the past decade, and the long standing questions concerning…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Tiziana Venturi , INAF , Istituto di Radioastronomia

We review observations of extended regions of radio emission in clusters; these include diffuse emission in `relics', and the large central regions commonly referred to as `halos'. The spectral observations, as well as Faraday rotation…

Astrophysics · Physics 2009-11-13 C. Ferrari , F. Govoni , S. Schindler , A. M. Bykov , Y. Rephaeli

Magnetic fields appear to be ubiquitous in astrophysical environments. Their existence in the intracluster medium is established through observations of synchrotron emission and Faraday rotation. On the other hand, the nature of magnetic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Dongsu Ryu , Dominik R. G. Schleicher , Rudolf A. Treumann , Christos G. Tsagas , Lawrence M. Widrow

The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. The most detailed evidence for the presence of cluster magnetic fields comes…

Astrophysics · Physics 2009-11-11 Federica Govoni

Theory and simulations suggest that magnetic fields from radio jets and lobes powered by their central super massive black holes can be an important source of magnetic fields in the galaxy clusters. This is paper II in a series of studies…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Hao Xu , Hui Li , David C. Collins , Shengtai Li , Michael L. Norman

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…

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…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-04 Gianfranco Brunetti

Both, X-ray and radio observations, are beginning to probe regions in galaxy clusters close to the virial radius. These are particularly interesting regions as they are (i) crucial for the thermal evolution of the intra-cluster medium and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 M. Bruggen , R. J. van Weeren , H. J. A. Rottgering