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Related papers: Yet another Odd Radio Circle?

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A measurable fraction ($\sim8$ per cent) of recently discovered arcmin-size circular diffuse radio sources termed as Odd Radio Circles or ORCs can be supernovae remnants in the intragroup medium, within the local group and its immediate…

Astrophysics of Galaxies · Physics 2022-04-12 A. Omar

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…

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…

Deep radio surveys are now producing catalogs with millions of radio sources. Radio sources can have complex morphologies that depend on both the production mechanisms and the local environment. Recently, an unusual class of circular radio…

A new class of radio source, the so-called Odd Radio Circles (ORCs), have been discovered by recent sensitive, large-area radio continuum surveys. The distances of these sources have so far relied on photometric redshifts of optical…

Astrophysics of Galaxies · Physics 2024-04-11 David Rupke , Alison Coil , Kelly Whalen , John Moustakas , Christy Tremonti , Serena Perrotta

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 origin of arcmin-sized Odd Radio Circles (ORCs) found in modern all-sky radio surveys remain uncertain, with explanations ranging from starburst/AGN-driven shocks to supernova remnants (SNRs) in the low-density ambient medium. Using…

Astrophysics of Galaxies · Physics 2022-09-23 Sumit K. Sarbadhicary , Todd A. Thompson , Laura A. Lopez , Smita Mathur

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

We present a systematic search for Odd Radio Circles (ORCs) and other unusual radio morphologies using data from the first year of the EMU (Evolutionary Map of the Universe) survey. ORCs are rare, enigmatic objects characterized by…

We report the discovery of J0624-6948, a low-surface brightness radio ring, lying between the Galactic Plane and the Large Magellanic Cloud (LMC). It was first detected at 888 MHz with the Australian Square Kilometre Array Pathfinder…

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

Mixed-morphology supernova remnants (MM SNRs) are a mysterious class of objects that display thermal X-ray emission within their radio shell. They are an older class of SNRs, and as such are profoundly affected by the environment into which…

High Energy Astrophysical Phenomena · Physics 2019-02-27 M. Arias , J. Vink , M. Iacobelli , V. Domcek , M. Haverkorn , J. B. R. Oonk , I. Polderman , W. Reich , G. J. White , P. Zhou

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…

Odd Radio Circles or ORCs are recently discovered edge-brightened, low surface brightness circular radio sources. The progenitors and astrophysical processes responsible for their origins are presently debated. Some ORCs are host-less and…

Astrophysics of Galaxies · Physics 2022-08-03 A. Omar

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 have imaged a 1 deg^2 field centered on the known Galactic supernova remnant (SNR) G11.2-0.3 at 74, 330, and 1465 MHz with the Very Large Array radio telescope (VLA) and 235 MHz with the Giant Metrewave Radio Telescope (GMRT). The 235,…

Odd Radio Circles (ORCs) are a new class of extragalactic object, with large rings of faint radio continuum emission typically spanning 100s of kpc; their origins are unknown. Previous optical spectroscopy of the central galaxy in ORC4, a…

Astrophysics of Galaxies · Physics 2026-04-15 Alison L. Coil , David S. N. Rupke , Serena Perrotta , Saloni Agrawal , Cassandra Lochhaas

Odd radio circles (ORCs) are mysterious rings of faint, diffuse emission recently discovered in radio surveys, some of which may be associated with galaxies in relatively dense environments. We propose such ORCs to be synchrotron emission…

High Energy Astrophysical Phenomena · Physics 2024-05-03 Yutaka Fujita , Norita Kawanaka , Susumu Inoue

We conducted an extensive identification and analysis of various morphological classes and subclasses of radio galaxies using the latest high-resolution data from the second data release of the LOFAR Two-Metre Sky Survey (LoTSS DR2). This…

Astrophysics of Galaxies · Physics 2026-04-29 Soumen Kumar Bera , Taotao Fang , Tapan K. Sasmal , M. Kunert-Bajraszewska , Xuelei Chen , Soumen Mondal
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