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We present the discovery of a new Odd Radio Circle (ORC J0219--0505) in 1.2~GHz radio continuum data from the MIGHTEE survey taken with the MeerKAT telescope. The radio-bright host is a massive elliptical galaxy, which shows extended…

Odd Radio Circles (ORCs) are recently-discovered faint diffuse circles of radio emission, of unknown cause, surrounding galaxies at moderate redshift ($z ~ 0.2-0.6). Here we present detailed new MeerKAT radio images at 1284 MHz of the first…

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…

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

We report the discovery of 164 compact (radius < 1 arcmin) radio rings using MeerKAT 1.3 GHz data from the SARAO MeerKAT Galactic Plane Survey (l=2-60deg, 252-358deg, |b|<1.5deg) and the Galactic Centre mosaic, from a search aimed at…

We present the discovery of another Odd Radio Circle (ORC) with the Australian Square Kilometre Array Pathfinder (ASKAP) at 944 MHz. The observed radio ring, ORC J0102-2450, has a diameter of ~70 arcsec or 300 kpc, if associated with the…

Odd Radio Circles (ORCs) are unexpected faint circles of diffuse radio emission discovered in recent wide deep radio surveys. They are typically about one arcmin in diameter, and may be spherical shells of synchrotron emission about a…

Astrophysics of Galaxies · Physics 2021-11-03 Ray P. Norris , Evan Crawford , Peter Macgregor

Odd Radio Circles (ORCs) are a class of low surface brightness, circular objects approximately one arcminute in diameter. ORCs were recently discovered in the Australian Square Kilometre Array Pathfinder (ASKAP) data, and subsequently…

Recently, a new population of circular radio ($\sim$GHz) objects have been discovered at high Galactic latitudes, called the Odd Radio Circles (ORCs). A fraction of the ORCs encircles massive galaxies in the sky with stellar mass $\sim…

High Energy Astrophysical Phenomena · Physics 2024-01-26 Shotaro Yamasaki , Kartick C. Sarkar , Zhaozhou Li

New observations with the current generation of advanced radio interferometers, such as ASKAP and MeerKAT, have led to the discovery of new classes of extended radio sources of unknown origin, including the so-called Odd Radio Circles…

We present three rare and striking extragalactic radio sources discovered through visual inspection of low-frequency continuum maps from LoTSS DR2 and TGSS by the RAD@home citizen-science collaboratory. The first, RAD J131346.9+500320, is…

Astrophysics of Galaxies · Physics 2025-10-03 Ananda Hota , Pratik Dabhade , Prasun Machado , Joydeep Das , Aarti Muley , Arundhati Purohit

The radio sky is poorly sampled for rapidly varying transients because of the narrow field-of-view of most imaging radio telescopes at cm and shorter wavelengths. The emergence of sensitive long wavelength observations with intrinsically…

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 the discovery of two intersecting radio shells, likely radio relics, surrounding a compact galaxy group dominated by a massive elliptical galaxy. The shells present as partial, edge-brightened rings with diameters of about 240"…

Astrophysics of Galaxies · Physics 2025-07-17 Bärbel S. Koribalski , Klaus Dolag , Ildar Khabibullin , Ludwig M. Böss , Anna Ivleva , Ray P. Norris

We present the discovery of a single radio relic located at the edge of the galaxy cluster A2384, using the MeerKAT radio telescope. A2384 is a nearby ($z$ = 0.092), low mass, complex bimodal, merging galaxy cluster that displays a dense…

We present the discovery of large radio shells around a massive pair of interacting galaxies and extended diffuse X-ray emission within the shells. The radio data were obtained with the Australian Square Kilometer Array Pathfinder (ASKAP)…

We identify a source (J1507+3013) with an extended diffuse radio emission around an elliptical galaxy from the Very Large Array (VLA) Faint Images of Radio Sky at Twenty-cm (FIRST) survey. J1507+3013 possesses a morphology similar to the…

Astrophysics of Galaxies · Physics 2025-06-19 Shobha Kumari , Sabyasachi Pal

The Odd Radio Circles are newly identified diffuse radio sources at ~1 GHz frequency, with edge-brightened nearly circular morphology, which is remarkably similar to supernova remnants although a physical association with previous…

High Energy Astrophysical Phenomena · Physics 2022-05-20 Amitesh Omar

Radio mini-haloes are poorly-understood, moderately-extended diffuse radio sources that trace the presence of magnetic fields and relativistic electrons on scales of hundreds of kiloparsecs, predominantly in relaxed clusters. With…

A new class of extragalactic astronomical sources discovered in 2021, named Odd Radio Circles (ORCs, Norris et al. 2021), are large rings of faint, diffuse radio continuum emission spanning ~1 arcminute on the sky. Galaxies at the centers…

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