Stingrays in the radio sky: Two unusual diffuse radio relic sources in the direction of the Magellanic Stream

Abstract We present the discovery of two extended, low surface-brightness radio continuum sources, each consisting of a near-circular body and an extended tail of emission, nicknamed Stingray 1 (ASKAP J0129–5350) and Stingray 2 (ASKAP J0245–5642). Both are found in the direction of the Magellanic Stream (MS) and were discovered in the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey at 944 MHz. We combine the ASKAP data with low-frequency radio observations from the GaLactic and Extragalactic All-sky MWA Survey (GLEAM) to conduct a radio continuum analysis. galaxy pairs or groups, and Odd Radio Circles (ORCs). We explore both Galactic/near Galactic scenarios, including runaway or circumgalactic supernova remnants (SNRs) and parentless pulsar-wind nebulae (PWNe), and extragalactic scenarios including radio active galactic nuclei (AGNs), dying radio galaxies, galaxy clusters, galaxy pairs or groups, head-tail radio galaxies, and ORCs, as well as the possibility that the morphology is due to a chance alignment. The Stingrays exhibit non-thermal emission with spectral indices of $\alpha=-0.89\pm0.09$ for Stingray 1 and $\alpha=-1.77\pm0.06$ for Stingray 2. We find that none of the proposed scenarios can explain all of the observed properties, however we determine it most likely that their shape is caused by some kind of complex environmental interaction. The most likely scenario from the available data is that of a head-tail radio galaxy, but more data is required for a definitive classification.

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Publication Details

Journal
Publications of the Astronomical Society of Australia
Published
2025-01-01
DOI
https://doi.org/10.1017/pasa.2025.10084
Primary Topic
Radio Astronomy Observations and Technology
Type
article
Field-Weighted Citation Impact
0.00

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article

Stingrays in the radio sky: Two unusual diffuse radio relic sources in the direction of the Magellanic Stream

Sanja Lazarević, Gavin Rowell, E. J. Crawford, Andrew Hopkins et al.
Publications of the Astronomical Society of Australia
Radio Astronomy Observations and Technology
article

Stingrays in the radio sky: Two unusual diffuse radio relic sources in the direction of the Magellanic Stream

Sanja Lazarević, Gavin Rowell, E. J. Crawford, Andrew Hopkins, Miroslav D Filipović, R. Z. E. Alsaberi, Peter J. Macgregor, Jacco Th. van Loon, N. Gupta, Stanislav S. Shabala, Tessa Vernstrom, D. A. Leahy, M. Sasaki, Andy Bradley, Shi Dai, F. Haberl, T. H. Jarrett, D. Urošević, B. Koribalski, Zachary J. Smeaton
article en

Abstract

Abstract We present the discovery of two extended, low surface-brightness radio continuum sources, each consisting of a near-circular body and an extended tail of emission, nicknamed Stingray 1 (ASKAP J0129–5350) and Stingray 2 (ASKAP J0245–5642). Both are found in the direction of the Magellanic Stream (MS) and were discovered in the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey at 944 MHz. We combine the ASKAP data with low-frequency radio observations from the GaLactic and Extragalactic All-sky MWA Survey (GLEAM) to conduct a radio continuum analysis. galaxy pairs or groups, and Odd Radio Circles (ORCs). We explore both Galactic/near Galactic scenarios, including runaway or circumgalactic supernova remnants (SNRs) and parentless pulsar-wind nebulae (PWNe), and extragalactic scenarios including radio active galactic nuclei (AGNs), dying radio galaxies, galaxy clusters, galaxy pairs or groups, head-tail radio galaxies, and ORCs, as well as the possibility that the morphology is due to a chance alignment. The Stingrays exhibit non-thermal emission with spectral indices of $\alpha=-0.89\pm0.09$ for Stingray 1 and $\alpha=-1.77\pm0.06$ for Stingray 2. We find that none of the proposed scenarios can explain all of the observed properties, however we determine it most likely that their shape is caused by some kind of complex environmental interaction. The most likely scenario from the available data is that of a head-tail radio galaxy, but more data is required for a definitive classification.

Publications of the Astronomical Society of AustraliaVol. 42
University of Tasmania (AU), Australia Telescope National Facility (AU), University of Cape Town (ZA), University of Calgary (CA), The University of Western Australia (AU), Friedrich-Alexander-Universität Erlangen-Nürnberg (DE), University of Belgrade (RS), Max Planck Institute for Extraterrestrial Physics (DE), Astronomical Observatory (RS), Gifu University (JP), Keele University (GB), The University of Adelaide (AU), Western Sydney University (AU), Macquarie University (AU)
National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, California Institute of Technology, Science and Industry Endowment Fund, Australian Government, Commonwealth Scientific and Industrial Research Organisation, Chinese Academy of Sciences, Government of Western Australia, Office of Science, Jet Propulsion Laboratory, Division of Astronomical Sciences, High Energy Physics, Lawrence Berkeley National Laboratory
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Radio Astronomy Observations and Technology
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