English
Related papers

Related papers: Collimated synchrotron threads linking the radio l…

200 papers

Radio observations over the last two decades have provided evidence that diffuse synchrotron emission in the form of megaparsec-scale radio halos in galaxy clusters is likely tracing regions of the intracluster medium where relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-25 G. Bernardi , T. Venturi , R. Cassano , D. Dallacasa , G. Brunetti , V. Cuciti , M. Johnston-Hollitt , N. Oozeer , O. M. Smirnov

The Bullet cluster (1E 0657-55.8) is a massive merging system at redshift $z$=0.296, known to host a powerful radio halo and a relic. Here we present high fidelity MeerKAT L-band (0.9-1.7 GHz) observations of the Bullet cluster, in which we…

Astrophysics of Galaxies · Physics 2022-11-30 S. P. Sikhosana , K. Knowles , M. Hilton , K. Moodley , M. Murgia

Feedback by radio-loud active galactic nuclei (AGN) in galaxy groups is not fully understood. Open questions include the duty cycle of the AGN, the spatial extent of the radio lobes, the effect they have on the intragroup medium, and the…

We report the discovery of the most distant radio galaxy to date, TGSS1530 at a redshift of $z=5.72$ close to the presumed end of the Epoch of Reionisation. The radio galaxy was selected from the TGSS ADR1 survey at 150 MHz for having to an…

We present the serendipitous discovery of (1) a large double radio relic associated with the galaxy cluster PSZ2 G277.93+12.34 and (2) a new odd radio circle, ORC J1027-4422, both found in the same deep MeerKAT 1.3 GHz wide-band radio…

The inner $\sim$200 pc region of the Galaxy contains a 4 million M$_{\odot}$ supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic ray energy densities that are roughly two orders of…

Astrophysics of Galaxies · Physics 2022-02-09 I. Heywood , I. Rammala , F. Camilo , W. D. Cotton , F. Yusef-Zadeh , T. D. Abbott , R. M. Adam , G. Adams , M. A. Aldera , K. M. B. Asad , E. F. Bauermeister , T. G. H. Bennett , H. L. Bester , W. A. Bode , D. H. Botha , A. G. Botha , L. R. S. Brederode , S. Buchner , J. P. Burger , T. Cheetham , D. I. L. de Villiers , M. A. Dikgale-Mahlakoana , L. J. du Toit , S. W. P. Esterhuyse , B. L. Fanaroff , S. February , D. J. Fourie , B. S. Frank , R. R. G. Gamatham , M. Geyer , S. Goedhart , M. Gouws , S. C. Gumede , M. J. Hlakola , A. Hokwana , S. W. Hoosen , J. M. G. Horrell , B. Hugo , A. I. Isaacson , G. I. G. Józsa , J. L. Jonas , A. F. Joubert , R. P. M. Julie , F. B. Kapp , J. S. Kenyon , P. P. A. Kotzé , N. Kriek , H. Kriel , V. K. Krishnan , R. Lehmensiek , D. Liebenberg , R. T. Lord , B. M. Lunsky , K. Madisa , L. G. Magnus , O. Mahgoub , A. Makhaba , S. Makhathini , J. A. Malan , J. R. Manley , S. J. Marais , A. Martens , T. Mauch , B. C. Merry , R. P. Millenaar , N. Mnyandu , O. J. Mokone , T. E. Monama , M. C. Mphego , W. S. New , B. Ngcebetsha , K. J. Ngoasheng , M. T. Ockards , N. Oozeer , A. J. Otto , S. S. Passmoor , A. A. Patel , A. Peens-Hough , S. J. Perkins , A. J. T. Ramaila , N. M. R. Ramanujam , Z. R. Ramudzuli , S. M. Ratcliffe , A. Robyntjies , S. Salie , N. Sambu , C. T. G. Schollar , L. C. Schwardt , R. L. Schwartz , M. Serylak , R. Siebrits , S. K. Sirothia , M. Slabber , O. M. Smirnov , L. Sofeya , B. Taljaard , C. Tasse , A. J. Tiplady , O. Toruvanda , S. N. Twum , T. J. van Balla , A. van der Byl , C. van der Merwe , V. Van Tonder , R. Van Wyk , A. J. Venter , M. Venter , B. H. Wallace , M. G. Welz , L. P. Williams , B. Xaia

Giant radio haloes are diffuse synchrotron sources typically found in merging galaxy clusters, while smaller mini-haloes occur in cool-core clusters. Both trace cosmic-ray electrons in the intracluster medium, though recent observations…

We report the discovery of an S-shaped morphology of the radio galaxy J0644$+$1043 imaged with a 30 $\mu$Jy sensitive 525 MHz broadband (band 3 $+$ 4) uGMRT map. Dedicated spectroscopic observations of the host galaxy carried out with the…

Astrophysics of Galaxies · Physics 2024-05-24 Sagar Sethi , Agnieszka Kuźmicz , Marek Jamrozy , Lyuba Slavcheva-Mihova

Context: Hierarchical galaxy formation models indicate that during their lifetime galaxy clusters undergo several mergers. Here we report on the discovery of three diffuse radio sources in the periphery of Abell 2256, using the GMRT. Aims:…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 R. J. van Weeren , H. T. Intema , J. B. R. Oonk , H. J. A. Rottgering , T. E. Clarke

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

We present LOFAR observations of one of the most spectacular objects in the radio sky: Abell 2255. This is a nearby ($z = 0.0806$) merging galaxy cluster hosting one of the first radio halos ever detected in the intra-cluster medium (ICM).…

Radio relics are diffuse extended synchrotron sources that originate from shock fronts induced by galaxy cluster mergers. The actual particle acceleration mechanism at the shock fronts is still under debate. The galaxy cluster 1RXS…

High Energy Astrophysical Phenomena · Physics 2020-04-15 K. Rajpurohit , M. Hoeft , F. Vazza , L. Rudnick , R. J. van Weeren , D. Wittor , A. Drabent , M. Brienza , F. Loi , E. Bonnassieux , N. Locatelli , R. Kale , C. Dumba

New observations of Sgr A have been carried out with the VLA using the broadband (2 GHz) continuum mode at 5.5 GHz, covering the central 30 pc region of the RBZ at the Galactic center. Using the MS-MFS algorithms in CASA, we have imaged Sgr…

Astrophysics of Galaxies · Physics 2016-02-17 Jun-Hui Zhao , Mark R. Morris , W. M. Goss

We report the discovery of a unique object in the MeerKAT Galaxy Cluster Legacy Survey (MGCLS) using the machine learning anomaly detection framework Astronomaly. This strange, ring-like source is 30' from the MGCLS field centred on Abell…

Astrophysics of Galaxies · Physics 2023-02-09 Michelle Lochner , Lawrence Rudnick , Ian Heywood , Kenda Knowles , Stanislav S. Shabala

Radio halos are elusive sources located at the center of merging galaxy clusters. To date, only about 40 radio halos are known, thus the discovery of new halos provide important insights on this class of sources. To improve the statistics…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 F. Govoni , C. Ferrari , L. Feretti , V. Vacca , M. Murgia , G. Giovannini , R. Perley , C. Benoist

We analyze all the available Atacama Large Millimeter / submillimeter Array archival data of the nearby Type-II Seyfert galaxy NGC 1068, including new 100 GHz data with the angular resolution of 0\farcs05, which was not included in previous…

Astrophysics of Galaxies · Physics 2023-08-02 Tomonari Michiyama , Yoshiyuki Inoue , Akihiro Doi

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

A recent Chandra observation of the nearby galaxy cluster Abell 585 has led to the discovery of an extended X-ray jet associated with the high-redshift background quasar B3 0727+409, a luminous radio source at redshift z=2.5. This is one of…

High Energy Astrophysical Phenomena · Physics 2016-01-13 A. Simionescu , Ł. Stawarz , Y. Ichinohe , C. C. Cheung , M. Jamrozy , A. Siemiginowska , K. Hagino , P. Gandhi , N. Werner

We present new radio observations of the galaxy cluster merger CIZA J0107.7+5408 (CIZA0107), a large, roughly equal mass, post-core passage, dissociative binary system at z = 0.1066. CIZA0107 is an elongated, disturbed system, hosting two…

In the current paradigm, high redshift radio halos are expected to be scarce due to inverse Compton energy losses and redshift dimming, which cause them to be intrinsically faint. This low occurrence fraction is predicted by cosmic ray…

High Energy Astrophysical Phenomena · Physics 2025-06-11 S. P. Sikhosana , M. Hilton , G. Bernardi , K. Kesebonye , D. Y. Klutse , K. Knowles , K. Moodley , T. Mroczkowski , B. Partridge , C. Sifón , C. Vargas , E. Wollack