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New radio and X-ray data are reported for the rich cluster Abell 2255. The cluster radio emission is characterized by the presence of a diffuse halo source, located at the cluster center, and a more peripheral ridge of radio emission which…

Astrophysics · Physics 2007-05-23 L. Feretti , H. Boehringer , G. Giovannini , D. Neumann

We present LOw Frequency ARray observations of the Coma cluster field at 144\,MHz. The cluster hosts one of the most famous radio halos, a relic, and a low surface-brightness bridge. We detect new features that allow us to make a step…

We present LOFAR data from 110--180~MHz of the merging galaxy cluster Abell 1682, alongside archival optical, radio and X-ray data. Our 6 arc-second resolution images at low frequencies reveal new structures associated with numerous radio…

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…

Astrophysics of Galaxies · Physics 2016-11-23 Viral Parekh , K. S. Dwarakanath , Ruta Kale , Huib Intema

We aim to carry out a radio study of the SoUthern Cluster sCale Extended Source Survey (SUCCESS) sample consisting of twenty massive (M$_{500} > 5\times10^{14}$ M$_{\odot}$), nearby (redshift $<0.3$) and southern ($-50^{\circ} < \delta <…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-23 R. Kale , V. Parekh , M. Rahaman , D. C. Joshi , T. Venturi , K. Kolokythas , J. O. Chibueze , S. Sikhosana , D. Pillay , K. Knowles

Radio relics in galaxy clusters are associated with powerful shocks that (re)accelerate relativistic electrons. It is widely believed that the acceleration proceeds via diffusive shock acceleration. In the framework of thermal leakage, the…

High Energy Astrophysical Phenomena · Physics 2015-05-13 F. Vazza , D. Eckert , M. Brueggen , B. Huber

In this Letter, we report the discovery of a radio halo in the high-redshift galaxy cluster PSZ2 G099.86+58.45 ($z=0.616$) with the LOw Frequency ARray (LOFAR) at 120-168 MHz. This is one of the most distant radio halos discovered so far.…

The presence of magnetic fields in galaxy clusters has been well established in recent years, and their importance for the understanding of the physical processes at work in the Intra Cluster Medium has been recognized. Halo and relic…

We present new LOFAR observations of the massive merging galaxy cluster MACS J0717.5+3745. The cluster hosts the most powerful radio halo known to date. These new observations, in combination with published uGMRT (300$-$850 MHz) and VLA…

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,…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-22 Ruta Kale , Krishna M. Shende , Viral Parekh

Some galaxy clusters show diffuse radio emission in the form of peripheral relics (so far attributed to primary, shock-(re)accelerated electrons) or central halos. Analysing radio and X-ray data from the literature, we find new connections…

High Energy Astrophysical Phenomena · Physics 2010-11-04 Uri Keshet

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

Modern radio telescopes are revolutionising our understanding of non-thermal phenomena in galaxy clusters, collecting large samples of extended sources with unprecedented sensitivity and angular resolution. In this work, we present novel…

Radio relics in galaxy clusters are extended synchrotron sources produced by cosmic-ray electrons in the $\mu$G magnetic field. Many relics are found in the cluster periphery and have a cluster-centric, narrow arc-like shape, which suggests…

High Energy Astrophysical Phenomena · Physics 2021-06-23 John A. ZuHone , Maxim Markevitch , Rainer Weinberger , Paul Nulsen , Kristian Ehlert

Diffuse cluster-scale synchrotron radio emission is discovered in an increasing number of galaxy clusters in the form of radio halos (RHs), probing the presence of relativistic electrons and magnetic fields in the intra-cluster medium. The…

Spiral structures and cold fronts in X-rays are frequently observed in cool core galaxy clusters. However, studies on radio mini-haloes associated with such spirals and their physical connections are rare. Here, we present the detection of…

Astrophysics of Galaxies · Physics 2024-06-21 S. K. Kadam , Sameer Salunkhe , N. D. Vagshette , Surajit Paul , Satish S. Sonkamble , P. K. Pawar , M. K. Patil

Galaxy clusters, the largest gravitationally bound objects in the Universe, are thought to grow by accreting mass from their surroundings through large-scale virial shocks. Due to electron acceleration in such a shock, it should appear as a…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-15 Uri Keshet , Doron Kushnir , Abraham Loeb , Eli Waxman

A2319 is a massive, merging galaxy cluster with a previously detected radio halo that roughly follows the X-ray emitting gas. We present the results from recent observations of A2319 at 20 cm with the Jansky Very Large Array (VLA) and a…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Emma Storm , Tesla E. Jeltema , Lawrence Rudnick

Radio halos are diffuse synchrotron sources that trace the turbulent intracluster medium (ICM) of galaxy clusters. However, their origin remains unknown. Two main formation models have been proposed: the hadronic model, in which…

The presence of non-thermal components in galaxy clusters is now clearly established. Diffuse radio emission from the Intra Cluster Medium (ICM) of several galaxy clusters is revealed in the form of radio halos and relics. These emissions…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-18 Rossella Cassano
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