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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…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 A. Bonafede , H. T. Intema , M. Brüggen , H. R. Russell , G. Ogrean , K. Basu , M. Sommer , R. J. van Weeren , R. Cassano , A. C. Fabian , H. J. A. Röttgering

Collisions of galaxy clusters generate shocks and turbulence in the intra-cluster medium (ICM). The presence of relativistic particles and magnetic fields is inferred through the detection of extended synchrotron radio sources such as…

Context. Radio halos are megaparsec-scale diffuse radio sources{ mostly} located at the centres of merging galaxy clusters. The common mechanism invoked to explain their origin is the re-acceleration of relativistic particles caused by…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 G. Di Gennaro , R. J. van Weeren , R. Cassano , G. Brunetti , M. Brüggen , M. Hoeft , E. Osinga , A. Botteon , V. Cuciti , F. de Gasperin , H. J. A. Röttgering , C. Tasse

We conduct an intensive study of the rich, X-ray luminous galaxy cluster A773 at z=0.22 containing a diffuse radio halo to determine its dynamical status. Our analysis is based on new spectroscopic data obtained at the TNG telescope for 107…

Astrophysics · Physics 2009-11-13 R. Barrena , W. Boschin , M. Girardi , M. Spolaor

Here we analyze radio, optical, and X-ray data for a peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy, CGPG 0719.8+6704, is a pair of interacting ellipticals…

High Energy Astrophysical Phenomena · Physics 2015-06-03 K. Hagino , L. Stawarz , A. Siemiginowska , C. C. Cheung , D. Koziel-Wierzbowska , A. Szostek , G. Madejski , D. E. Harris , A. Simionescu , T. Takahashi

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…

Massive galaxy clusters with cool-cores typically host diffuse radio sources called mini-haloes, whereas, those with non-cool-cores host radio haloes. We attempt to understand the unusual nature of the cool-core galaxy cluster CL1821+643…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-08 Ruta Kale , Viral Parekh

The presence of non-thermal electrons and large scale magnetic fields in the intra-cluster medium (ICM) is known through the detection of mega-parsec (Mpc) scale diffuse radio synchrotron emission. Although a significant amount of progress…

High Energy Astrophysical Phenomena · Physics 2020-11-04 Ramij Raja , Majidul Rahaman , Abhirup Datta , Reinout J. van Weeren , Huib T. Intema , Surajit Paul

(abridged) We present a detailed reanalysis of the Chandra data for the galaxy cluster Abell 4059 and its central radio galaxy, PKS2354-35. We also present new 1.4GHz and 4.7GHz CnB-array radio data from the Very Large Array (VLA), as well…

Spectral index images can be used to constraint the energy spectrum of relativistic electrons and magnetic field distribution in radio halos and relics, providing useful information to understand their formation, evolution and connection to…

Astrophysics · Physics 2009-11-13 E. Orru' , M. Murgia , L. Feretti , F. Govoni , G. Brunetti , G. Giovannini , M. Girardi , G. Setti , .

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…

Astrophysics · Physics 2007-05-23 L. Feretti

Diffuse radio emission has been found in many galaxy clusters, predominantly in massive systems which are in the state of merging. The radio emission can usually be classified as relic or halo emission, which are believed to be related to…

We present 74 MHz and 330 MHz VLA observations of Abell 754. Diffuse, halo-like emission is detected from the center of the cluster at both frequencies. At 330 MHz the resolution of 90'' distinguishes this extended emission from previously…

Astrophysics · Physics 2009-11-06 N. E. Kassim , T. E. Clarke , T. A. Enßlin , A. S. Cohen , D. M. Neumann

In this paper we present new high sensitivity 153 MHz Giant Meterwave Radio Telescope follow-up observations of the diffuse steep spectrum cluster radio sources in the galaxy clusters Abell 521, Abell 697, Abell 1682. Abell 521 hosts a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 G. Macario , T. Venturi , H. T. Intema , D. Dallacasa , G. Brunetti , R. Cassano , S. Giacintucci , C. Ferrari , C. H. Ishwara-Chandra , R. Athreya

We investigate the possible presence of diffuse radio emission in the intermediate redshift, massive cluster PLCK G285.0-23.7 (z=0.39, M_500 = 8.39 x 10^(14) M_Sun). Our 16cm-band ATCA observations of PLCK G285.0-23.7 allow us to reach a…

Many relaxed cool-core clusters host diffuse radio emission on scales of hundreds of kiloparsecs: mini-haloes. However, the mechanism responsible for generating them, as well as their connection with central active galactic nuclei, is…

We report the detection of a diffuse radio halo source in the hottest known cluster of galaxies 1E0658-56 (RXJ0658-5557). The radio halo has a morphology similar to the X-ray emission from the hot intracluster medium. The detection of such…

Astrophysics · Physics 2007-05-23 H. Liang

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…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 A. Bonafede , M Brueggen , R. van Weeren , F. Vazza , G. Giovannini , H. Ebeling , A. C. Edge , M. Hoeft , U. Klein

we present new VLA observations at 1.4 GHz confirming the presence of a radio halo at the centre of the cluster A3562, in the core of the Shapley Concentration. We also report a detailed multifrequency radio study of the head tail galaxy…

Mergers between galaxy clusters often drive shocks into the intra cluster medium (ICM), the effects of which are sometimes visible via temperature and density jumps in the X-ray, and via radio emission from relativistic particles energized…