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In this paper we analyze the peculiar radio structure observed across the central region of the galaxy cluster Abell 585 (z=0.12). In the low-resolution radio maps, this structure appears uniform and diffuse on angular scales of ~3 arcmin,…

Astrophysics of Galaxies · Physics 2015-06-19 M. Jamrozy , Ł Stawarz , V. Marchenko , A. Kuzmicz , M. Ostrowski , C. C. Cheung , M. Sikora

We report the discovery of a radio megahalo in the merging cluster PLCKG287.0+32.9, based on upgraded Giant Metrewave Radio telescope (uGMRT) observations at frequencies 300-850 MHz. The sensitive radio observations provide a new window to…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-18 Sameer Salunkhe , Ramananda Santra , Ruta Kale

Galaxy clusters have been found to host a range of diffuse, non-thermal emission components, generally with steep, power law spectra. In this work we report on the detection and follow-up of radio halos, relics, remnant radio galaxies, and…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-20 S. W. Duchesne , M. Johnston-Hollitt , I. Bartalucci

We present a Chandra observation of the merging cluster of galaxies Abell 2744. The cluster shows strong evidence for an ongoing major merger which we believe to be responsible for the radio halo. X-ray emission and temperature maps of the…

Astrophysics · Physics 2009-11-10 Joshua C. Kempner , Laurence P. David

We present results on 12 X-ray bright clusters observed at 1.4 GHz with the Green Bank Telescope. After subtraction of point sources, we reach a median (best) 1-sigma noise level of 0.01 (0.006) microJy/sq. arcsec, and find a significant…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Damon Farnsworth , Lawrence Rudnick , Shea Brown , Gianfranco Brunetti

We have performed the the first census of Mpc-scale radio emission to include control fields and quantifiable upper limits for bright X-ray clusters in the range 0.03<z<0.3 . Through reprocessing radio images from the WENSS survey, we…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-15 Lawrence Rudnick , Jeffrey Lemmerman

In some clusters of galaxies, a diffuse non-thermal emission is present, not obviously associated with any individual galaxy. These sources have been identified as relics, mini-halos, and halos according to their properties and position…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 G. Giovannini , A. Bonafede , L. Feretti , F. Govoni , M. Murgia

We present VLA radio and Chandra X-ray observations of the merging galaxy cluster Abell 3411. For the cluster, we find an overall temperature of 6.4 keV and an X-ray luminosity of 2.8 x 10^{44} erg s^{-1} between 0.5 and 2.0 keV. The…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-23 R. J. van Weeren , K. Fogarty , C. Jones , W. R. Forman , T. E. Clarke , M. Bruggen , R. P. Kraft , D. V. Lal , S. S. Murray , H. J. A. Rottgering

We present the first band-2 (120--250\,MHz) uGMRT (upgraded Giant Metrewave Radio Telescope) observations of the bimodal galaxy cluster Abell\,1644 (\(z = 0.0471\)), complemented by Chandra X-ray data. While weak lensing measurements reveal…

Astrophysics of Galaxies · Physics 2025-12-24 Humaira Bashir , R. Kale , Asif Iqbal , Manzoor A. Malik

Clusters of galaxies are excellent laboratories for studying recurring nuclear activity in galactic nuclei since their hot gaseous medium can vastly prolong the detectability of their radio lobes via better confinement. We report here a…

Astrophysics of Galaxies · Physics 2022-08-31 Sameer Salunkhe , Surajit Paul , Gopal-Krishna , Satish Sonkamble , Shubham Bhagat

Diffuse radio sources, known as mini-halos and halos, are detected at the centres of galaxy clusters. These centralized diffuse sources are typically observed individually, with both appearing together only in rare cases. The origin of the…

High Energy Astrophysical Phenomena · Physics 2025-03-26 D. N. Hoang , M. Brüggen , A. Bonafede , P. M. Koch , G. Brunetti , E. Bulbul , G. Di Gennaro , A. Liu , C. J. Riseley , H. J. A. Röttgering , R. J. van Weeren

The aim of this work is to analyse the radio properties of the massive and dynamical disturbed clusters Abell 1451 and Zwcl 0634.1+4750, especially focusing on the possible presence of diffuse emission. We present new GMRT 320 MHz and JVLA…

Astrophysics of Galaxies · Physics 2018-01-10 V. Cuciti , G. Brunetti , R. van Weeren , A. Bonafede , D. Dallacasa , R. Cassano , T. Venturi , R. Kale

We present radio observations of the galaxy cluster Abell S1136 at 888 MHz, using the Australian Square Kilometre Array Pathfinder radio telescope, as part of the Evolutionary Map of the Universe Early Science program. We compare these…

Multiwavelength studies of galaxy clusters are crucial for understanding the complex interconnection of the thermal and non-thermal constituents of these massive structures and uncovering the physical processes involved in their formation…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-24 Swarna Chatterjee , Denisha Pillay , Abhirup Datta , Ramij Raja , Kenda Knowles , Majidul Rahaman , S. P. Sikhosana

Recent advances in high-sensitivity radio observations have uncovered a population of faint, ultra-steep-spectrum sources in galaxy clusters, commonly known as radio phoenixes. However, their observational classification remains poorly…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-28 Nasmi S Anand , Swarna Chatterjee , Ramij Raja , Majidul Rahaman , Abhirup Datta

Diffuse radio emission at the centre of galaxy clusters has been observed both in merging clusters on scales of Mpc, called giant radio haloes, and in relaxed systems with a cool-core on smaller scales, named mini haloes. Giant radio haloes…

Relativistic electrons and magnetic fields permeate the intra-cluster medium (ICM) and manifest themselves as diffuse sources of synchrotron emission observable at radio wavelengths, namely radio halos and radio relics. Although there is…

We present the results of a joint XMM-Newton and NuSTAR observation (200 ks) of the galaxy cluster Abell 523 at $z=0.104$. The peculiar morphology of the cluster radio halo and its outlier position in the radio power P(1.4 GHz) - X-ray…

Radio halos are synchrotron radio sources detected in some massive galaxy clusters. Their Mpc-size indicates that (re)acceleration processes are taking place in the host cluster. X-ray catalogues of galaxy clusters have been used in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-28 A. Bonafede , H. T. Intema , M. Brüggen , F. Vazza , K. Basu , M. Sommer , H. Ebeling , F. de Gasperin , H. J. A. Röttgering , R. J. van Weeren , R. Cassano

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
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