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相关论文: Mpc-scale diffuse radio emission in two massive co…

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We report on a spectral study at radio frequencies of the giant radio halo in A2142 (z=0.0909), which we performed to explore its nature and origin. A2142 is not a major merger and the presence of a giant radio halo is somewhat surprising.…

宇宙学与河外天体物理 · 物理学 2017-07-26 T. Venturi , M. Rossetti , G. Brunetti , D. Farnsworth , F. Gastaldello , S. Giacintucci , D. V. Lal , L. Rudnick , T. W. Shimwell , D. Eckert , S. Molendi , M. Owers

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…

高能天体物理现象 · 物理学 2020-11-04 Ramij Raja , Majidul Rahaman , Abhirup Datta , Reinout J. van Weeren , Huib T. Intema , Surajit Paul

Diffuse radio sources associated with the intra-cluster medium are direct probes of the cosmic ray electrons and magnetic fields. We report the discovery of a diffuse radio source in the galaxy cluster RXCJ0232.2-4420 (SPT-CL J0232-4421,…

宇宙学与河外天体物理 · 物理学 2019-05-22 Ruta Kale , Krishna M. Shende , Viral Parekh

The most important evidence of non-thermal phenomena in galaxy clusters comes from Giant Radio Halos (GRHs), synchrotron radio sources extended over Mpc scales, detected in a growing number of massive galaxy clusters. A promising…

天体物理学 · 物理学 2009-11-11 R. Cassano , G. Brunetti , G. Setti

We analyze sensitive, high-dynamic-range, observations to search for extended, diffuse, radio emission in relaxed and cool-core galaxy clusters. We performed deep 1.4 GHz Very Large Array observations, of A1068, A1413, A1650, A1835, A2029,…

宇宙学与河外天体物理 · 物理学 2015-05-13 F. Govoni , M. Murgia , M. Markevitch , L. Feretti , G. Giovannini , G. B. Taylor , E. Carretti

We present a numerical model for the extended steep-spectrum radio sources and the elongated X-ray structure in A3667 based on new 3-dimensional MHD/N-body simulations. The X-ray and optical analyses of A3667 indicate that it has undergone…

天体物理学 · 物理学 2009-10-31 K. Roettiger , J. O. Burns , J. M. Stone

We search for extended regions of radio emission not associated with Active Galactic Nuclei, known as 'relics', 'halos' and 'mini halo's, in a sample of 70 Abell clusters for which we have radio, optical and X-ray data. AGN can produce…

宇宙学与河外天体物理 · 物理学 2012-09-05 Nectaria A. B. Gizani

We present the preliminary results of 235 MHz, 327 MHz and 610 MHz observations of the galaxy cluster A3562 in the core of the Shapley Concentration. The purpose of these observations, carried out with the Giant Metrewave Radio Telescope…

天体物理学 · 物理学 2009-11-10 S. Giacintucci , T. Venturi , S. Bardelli , G. Brunetti , D. Dallacasa , P. Rao , E. Zucca

We performed GMRT low frequency observations of the radio halos, relics and new candidates belonging to the GMRT Radio Halo Cluster Sample first observed at 610 MHz. High sensitivity imaging was performed using the GMRT at 325 MHz and 240…

The goal of the present study is to extend our current knowledge of the diffuse radio source (halo and relic) populations to $z$ $>$ 0.3. Here we report GMRT and EVLA radio observations of six galaxy clusters taken from the MAssive Cluster…

星系天体物理 · 物理学 2016-11-23 Viral Parekh , K. S. Dwarakanath , Ruta Kale , Huib Intema

Observations of giant radio halos provide unambiguous evidence for the existence of cosmic ray (CR) electrons and magnetic fields in galaxy clusters. The physical mechanism generating radio halos is still heavily debated. We critically…

高能天体物理现象 · 物理学 2011-09-28 Christoph Pfrommer , Torsten Ensslin , Francesco Miniati , Kandaswamy Subramanian

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…

宇宙学与河外天体物理 · 物理学 2016-08-08 Ruta Kale , Viral Parekh

In this letter we present a morphological comparison between giant radio halos and radio mini-halos in galaxy clusters based on radio--X-ray luminosity, P_{1.4}-L_X, and radio luminosity-size, P_{1.4}-R_H, correlations. We report evidence…

天体物理学 · 物理学 2009-11-13 R. Cassano , M. Gitti , G. Brunetti

The presence of megaparsec-scale radio halos in galaxy clusters has already been established by many observations over the last two decades. The emerging explanation for the formation of these giant sources of diffuse synchrotron radio…

宇宙学与河外天体物理 · 物理学 2017-03-15 G. Bernardi , T. Venturi , R. Cassano , D. Dallacasa , G. Brunetti , V. Cuciti , M. Johnston-Hollitt , N. Oozeer , V. Parekh , O. M. Smirnov

Collisions between galaxy clusters dissipate enormous amounts of energy in the intra-cluster medium (ICM) through turbulence and shocks. In the process, Mpc-scale diffuse synchrotron emission in form of radio halos and relics can form.…

New radio data at 330 MHz are presented for the rich clusters Abell 665 and Abell 2163, whose radio emission is characterized by the presence of a radio halo. These images allowed us to derive the spectral properties of the two clusters…

天体物理学 · 物理学 2009-11-10 L. Feretti , E. Orru' , G. Brunetti , G. Giovannini , N. Kassim , G. Setti

We examine the possible acceleration mechanisms of the relativistic particles responsible for the extended radio emission in Abell 520. We used new LOFAR 145 MHz, archival GMRT 323 MHz and VLA 1.5 GHz data to study the morphological and…

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…

宇宙学与河外天体物理 · 物理学 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 report the detection of a diffuse radio halo source in the hottest known cluster of galaxies 1E0657-56 (RXJ0658-5557). The radio halo has a morphology similar to the X-ray emission from the hot intracluster medium. The presence of a…

天体物理学 · 物理学 2009-10-31 H. Liang , R. W. Hunstead , M. Birkinshaw , P. Andreani

Large-scale magnetic fields reveal themselves through diffuse synchrotron sources observed in galaxy clusters such as radio halos. Total intensity filaments of these sources have been observed in polarization as well, but only in three…