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We present detailed observations of MRC 0116+111, revealing a luminous, mini radio-halo of ~240 kpc diameter located at the centre of a cluster of galaxies at redshift z = 0.131. Our optical and multi-wavelength GMRT and VLA radio…

宇宙学与河外天体物理 · 物理学 2015-05-13 Joydeep Bagchi , Joe Jacob , Gopal-Krishna , Norbert Werner , Nitin Wadnerkar , Jaydeep Belapure , A. C. Kumbharkhane

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…

高能天体物理现象 · 物理学 2015-06-23 Emma Storm , Tesla E. Jeltema , Lawrence Rudnick

To explore the high frequency radio spectra of galaxies in clusters, we used NRAO's Very Large Array at four frequencies, 4.9-43 GHz, to observe 139 galaxies in low redshift (z<0.25), X-ray detected, clusters. The clusters were selected…

It is argued that the new morphological and spectral information gleaned from the recently published LoFAR Two meter Sky Survey data release 2 (LoTSS-2 at 144 MHz) observations of the cluster Abell 980 (A980), in combination with its…

星系天体物理 · 物理学 2026-04-23 Gopal-Krishna , Surajit Paul , Sameer Salunkhe , Satish Sonkamble

Galaxy clusters are among the most massive gravitationally bound systems in the Universe and are considered major reservoirs of high-energy cosmic rays, yet no conclusive $\gamma$-ray detection from them has been achieved. This…

高能天体物理现象 · 物理学 2025-11-20 Gajanan D Harale , Surajit Paul

(Abridged) We describe the results of the highest-resolution radio observations yet made of four relic radio sources in the Abell clusters A13, A85, A133 and A4038. Our VLA images at 1.4 GHz with 4" resolution show a remarkable variety of…

天体物理学 · 物理学 2009-11-06 O. B. Slee , A. L. Roy , M. Murgia , H. Andernach , M. Ehle

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

Here we present Halo-FDCA, a robust open source Python package for modeling and estimating total flux densities of radio (mini) halos in galaxy clusters. Radio halos are extended ( ~200 - 1500 kpc in size) synchrotron emitting sources found…

宇宙学与河外天体物理 · 物理学 2021-04-26 J. M. Boxelaar , R. J. van Weeren , A. Botteon

Clusters of galaxies host spectacular diffuse radio sources, extending over scales from 100 kpc to several Mpcs. These sources, with extremely faint surface brightness ($\mu$Jy/arcsec$^2$ level), are not tied to individual galaxies but…

Recent X-ray and Sunyaev-Zel'dovich (SZ) observations have dramatically increased the number of known distant galaxy clusters. In some merging, low-redshift (z<0.4) clusters, centrally-located, diffuse, extended radio emission (called radio…

Recent low-frequency radio observations at 140 MHz discovered a 3 Mpc-long bridge of diffuse emission connecting the galaxy clusters Abell 0399 and Abell 0401. We present follow-up observations at 60 MHz to constrain the spectral index of…

New multi-wavelength (radio, optical & X-rays) observational evidences are presented which show that the nearby (z=0.046), rich cluster of galaxies Abell 3376 is experiencing a major event of binary subcluster merger. The key evidence is…

天体物理学 · 物理学 2007-05-23 Joydeep Bagchi

We present new measurements of the diffuse radio halo emission from the Coma cluster of galaxies at 2.675 GHz and 4.85 GHz using the Effelsberg 100--m telescope. After correction for the contribution from point sources we derive the…

天体物理学 · 物理学 2011-07-18 M. Thierbach , U. Klein , R. Wielebinski

Radio phoenices are complex and filamentary diffuse radio sources found in both merging and relaxed clusters. The formation of these sources was proposed to be due to adiabatic compression of old Active Galactic Nucleus (AGN) plasma in…

高能天体物理现象 · 物理学 2024-08-30 Ramij Raja , Majidul Rahaman , Abhirup Datta , Oleg M. Smirnov

We report the discovery of J1218+1813, a circular diffuse radio source detected in the Very Large Array (VLA) FIRST survey at 1400 MHz. The source has an angular diameter of approximately one arcminute, corresponding to a physical size of…

星系天体物理 · 物理学 2025-06-24 Shobha Kumari , Sabyasachi Pal , Souvik Manik

The largest galaxy clusters are observed still to be forming through major cluster-cluster mergers, often showing observational signatures such as radio relics and giant radio haloes. Using LOFAR Two-meter Sky Survey data, we present new…

We present the results of the dynamical analysis of the rich, hot, and X-ray very luminous galaxy cluster A2219, containing a powerful diffuse radio-halo. Our analysis is based on new redshift data for 27 galaxies in the cluster region,…

天体物理学 · 物理学 2009-11-10 W. Boschin , M. Girardi , R. Barrena Delgado , A. Biviano , L. Feretti , M. Ramella

We present deep XMM-Newton, Karl Jansky Very Large Array, and upgraded Giant Metrewave Radio Telescope observations of Abell 746, a cluster that hosts a plethora of diffuse emission sources that provide evidence for the acceleration of…

We have detected a radio bridge of unpolarized synchrotron emission connecting the NW relic of the galaxy cluster Abell 3667 to its central regions. We used data at 2.3 GHz from the S-band Polarization All Sky Survey (S-PASS) and at 3.3 GHz…

宇宙学与河外天体物理 · 物理学 2015-06-05 E. Carretti , S. Brown , L. Staveley-Smith , J. M. Malarecki , G. Bernardi , B. M. Gaensler , M. Haverkorn , M. J. Kesteven , S. Poppi

Here we investigate the giant radio galaxy DA 240, which is a FR II source. Specifically, we investigate its flux density, as well as the spectral index distribution. For that purpose, we used publicly available data for the source: Leahy's…

星系天体物理 · 物理学 2023-10-24 V. Borka Jovanović , D. Borka , P. Jovanović