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We report upgraded Giant Metrewave Radio Telescope and Karl J. Jansky Very Large Array radio observations of a low-mass merging galaxy cluster PSZ2 G181.06+48.47. This exceptional galaxy cluster hosts two megaparsec-scale diffuse sources,…

Giant radio halos are Mpc-scale diffuse radio sources associated with the central regions of galaxy clusters. The most promising scenario to explain the origin of these sources is that of turbulent re-acceleration, in which MeV electrons…

High Energy Astrophysical Phenomena · Physics 2017-07-26 D. Eckert , M. Gaspari , F. Vazza , F. Gastaldello , A. Tramacere , S. Zimmer , S. Ettori , S. Paltani

Non-thermal properties of galaxy clusters have been studied with detailed and deep radio images in comparison with X-ray data. While much progress has been made, most of the studied clusters are at a relatively low redshift (z < 0.3). We…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-26 G. Giovannini , M. Cau , A. Bonafede , H. Ebeling , L. Feretti , M. Girardi , M. Gitti , F. Govoni , A. Ignesti , M. Murgia , G. B. Taylor , V. Vacca

Galaxy clusters undergo mergers that can generate extended radio sources called radio relics. Radio relics are the consequence of merger-induced shocks that propagate in the intra cluster medium (ICM). In this paper we analyse the radio,…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-21 F. de Gasperin , H. T. Intema , J. Ridl , M. Salvato , R. van Weeren , A. Bonafede , J. Greiner , R. Cassano , M. Bruggen

Radio observations discovered large scale non thermal sources in the central Mpc regions of dynamically disturbed galaxy clusters (radio halos). The morphological and spectral properties of these sources suggest that the emitting electrons…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 G. Brunetti , A. Lazarian

There has been a growing body of evidence to suggest that AGN activity, which is powered by mass accretion on to a supermasive black hole, could be episodic, although the range of time scales involved needs to be explored further. The…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-16 D. J. Saikia , M. Jamrozy

A fraction of galaxy clusters harbor diffuse radio sources known as radio halos. The currently adopted scenario for their formation is based on second-order Fermi re-acceleration of seed electrons that is driven by merger-driven turbulence…

We present intermediate resolution, wide wavelength coverage spectra for a complete sample of 14 compact radio sources taken with the aim of investigating the impact of the nuclear activity on the circumnuclear (ISM) in the early stages of…

Astrophysics · Physics 2009-11-13 J. Holt , C. N. Tadhunter , R. Morganti

We analyze optical and radio properties of radiogalaxies detected in the Sloan Digital Sky Survey (SDSS). The sample of radio sources are selected from the catalogue of Kimball & Ivezi\'c (2008) with flux densities at 325, 1400 and 4850…

Astrophysics of Galaxies · Physics 2015-05-18 Carlos G. Bornancini , Ana Laura O'Mill , Sebastian Gurovich , Diego Garcia Lambas

We present results from the Very Long Baseline Array (VLBA) multi-frequency (1.6, 4.4, 8.6, 22 GHz), high-sensitivity (~25 microJy beam^-1), sub-parsec scale (<1 pc) observations and Spectral Energy Distributions (SEDs) for a sample of 12…

The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147 MHz and 1.4 GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey…

Instrumentation and Methods for Astrophysics · Physics 2018-01-10 F. de Gasperin , H. T. Intema , D. A. Frail

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

Using radio sources from the Faint Images of the Radio Sky at Twenty-cm (FIRST) survey, and optical counterparts in the Sloan Digital Sky Survey (SDSS), we have identified a large number of galaxy clusters. The radio sources within these…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-03 Joshua D. Wing , Elizabeth L. Blanton

We present a sample of 1,483 sources that display spectral peaks between 72 MHz and 1.4 GHz, selected from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. The GLEAM survey is the widest fractional bandwidth…

We present multi-frequency and high-resolution studies of a sample of 24 radio transients sources discovered by comparing the NRAO VLA Sky Survey (NVSS) and Very Large Array Sky Survey (VLASS) surveys. All of them are characterized by a…

Astrophysics of Galaxies · Physics 2024-12-11 M. Kunert-Bajraszewska , A. Krauze , A. E. Kimball , L. Stawarz , P. Kharb , D. Stern , K. Mooley , K. Nyland , D. Koziel-Wierzbowska

We present a follow-up study focused on cluster-scale diffuse radio emissions in 115 galaxy clusters in the Southern sky, using full-resolution (7.8") and tapered low-resolution (15") images from the MeerKAT Galaxy Cluster Legacy Survey…

Using observations obtained with the LOw Fequency ARray (LOFAR), the Westerbork Synthesis Radio Telescope (WSRT) and archival Very Large Array (VLA) data, we have traced the radio emission to large scales in the complex source 4C 35.06…

Radio relics are giant ($\sim$Mpc) synchrotron sources that are believed to be produced by the (re)acceleration of cosmic-ray electrons (CRe) by shocks in the intracluster medium. In this numerical study, we focus on the possibility that…

High Energy Astrophysical Phenomena · Physics 2021-10-27 Giannandrea Inchingolo , Denis Wittor , Kamlesh Rajpurohit , Franco Vazza

Based on the ATLBS survey we present a sample of extended radio sources and derive morphological properties of faint radio sources. 119 radio galaxies form the ATLBS-Extended Source Sample (ATLBS-ESS) consisting of all sources exceeding 30"…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 L. Saripalli , R. Subrahmanyan , K. Thorat , R. D. Ekers , R. W. Hunstead , H. M. Johnston , E. M. Sadler

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…