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Related papers: LOFAR observations of galaxy clusters in HETDEX

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Turbulence introduced into the intra-cluster medium (ICM) through cluster merger events transfers energy to non-thermal components, and can trigger the formation of diffuse synchrotron radio sources. Typical diffuse sources in the forms of…

Deep polarization surveys at low radio frequencies are key to cosmic magnetism studies: Larger catalogs of polarized extragalactic sources and increased precision on Faraday rotation measures (RMs) make it possible to probe the…

Astrophysics of Galaxies · Physics 2025-01-08 S. Piras , C. Horellou , J. Conway , M. Thomasson , T. W. Shimwell , S. P. O'Sullivan , E. Carretti , V. Vacca , A. Bonafede , I. Prandoni

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 Low Frequency Array (LOFAR) is the only existing radio interferometer able to observe at ultra-low frequencies (<100 MHz) with high resolution (<15") and high sensitivity (<1 mJy/beam). To exploit these capabilities, the LOFAR Surveys…

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…

Cosmological simulations predict the presence of warm hot thermal gas in the cosmic filaments that connect galaxy clusters. This gas is thought to constitute an important part of the missing baryons in the Universe. In addition to the…

Source classifications, stellar masses and star formation rates are presented for 80,000 radio sources from the first data release of the Low Frequency Array Two-metre Sky Survey (LoTSS) Deep Fields, which represents the widest deep radio…

We have used archival GMRT data to image and study 39 galaxy clusters. These observations were made as part of the GMRT Key Project on galaxy clusters between 2001 and 2004. The observations presented in this sample include 14 observations…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-18 Lijo T. George , Ruta Kale , Yogesh Wadadekar

Diffuse radio sources known as radio relics are direct tracers of shocks in the outskirts of merging galaxy clusters. PSZ2 G200.95-28.16, a low-mass merging cluster($\textrm{M}_{500} = (2.7 \pm 0.2) \times 10^{14}~\mathrm{M}_{\odot}$)…

Astrophysics of Galaxies · Physics 2024-11-26 Arpan Pal , Ruta Kale , Qian H. S. Wang , Daniel R. Wik

At very low frequencies, the new pan-European radio telescope LOFAR is opening the last unexplored window of the electromagnetic spectrum for astrophysical studies. The revolutionary APERTIF phased arrays that are about to be installed on…

Synchrotron radio halos at the center of merging galaxy clusters provide the most spectacular and direct evidence of the presence of relativistic particles and magnetic fields associated with the intracluster medium. The study of polarized…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 F. Govoni , M. Murgia , H. Xu , H. Li , M. L. Norman , L. Feretti , G. Giovannini , V. Vacca

About 1/3 of X-ray-luminous clusters show smooth, unpolarized radio emission on ~Mpc scales, known as giant radio halos. One promising model for radio halos is Fermi-II acceleration of seed relativistic electrons by turbulence of the…

High Energy Astrophysical Phenomena · Physics 2015-03-30 Anders Pinzke , S. Peng Oh , Christoph Pfrommer

Using the filled bolometer array SHARC-II on the Caltech Submillimeter Observatory (CSO), we have obtained deep (rms ~ 15mJy/beam), high-quality 350 micron maps of five of the most luminous high-z radio galaxies known. In all cases the…

Astrophysics · Physics 2009-11-11 T. R. Greve , R. J. Ivison , J. A. Stevens

We present radio observations of the galaxy cluster PLCK G004.5-19.5 ($z=0.52$) using the Giant Metrewave Radio Telescope at 150~MHz, 325~MHz, and 610~MHz. We find an unusual arrangement of diffuse radio emission in the center and periphery…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-01 J. G. Albert , C. Sifón , A. Stroe , F. Mernier , H. T. Intema , H. J. A. Röttgering , G. Brunetti

Radio galaxy PKS 1138-262 is a massive galaxy at z=2.16, located in a dense environment. We have found an overdensity of Ly-alpha emitting galaxies in this field, consistent with a proto-cluster structure associated with the radio galaxy.…

Astrophysics · Physics 2009-11-10 J. D. Kurk , L. Pentericci , R. A. Overzier , H. J. A. Roettgering , G. K. Miley

Observations of diffuse, non-thermal radio emission spanning several megaparsecs have been documented in over 100 galaxy clusters. This emission, classified as giant radio halos (GHs), mini halos, and radio relics based mainly on their…

High Energy Astrophysical Phenomena · Physics 2024-04-23 Doron Kushnir , Uri Keshet , Eli Waxman

Galaxy clusters with signs for a recent merger show in many cases extended diffuse radio features. This emission originates from relativistic electrons which suffer synchrotron losses due to the intra-cluster magnetic field. The mechanisms…

Astrophysics of Galaxies · Physics 2015-02-11 A. Drabent , M. Hoeft , R. F. Pizzo , A. Bonafede , R. J. van Weeren , U. Klein

Radio observations represent a powerful probe of the physics occurring in the intracluster medium (ICM) because they trace the relativistic cosmic rays in the cluster magnetic fields, or within galaxies themselves. By probing the low-energy…

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…

Giant radio halos are the Mpc-scale extended sources associated with the merging clusters, while the mini-halos are preferentially associated with cool-core clusters. Both trace the ICM plasma physical process, and recent low-frequency…

Astrophysics of Galaxies · Physics 2026-05-01 Pralay Biswas , Ramananda Santra , Ruta Kale , Viral Parekh