What the study found
The study reports two intersecting radio shells, called ORC J1841–6547 or ORC 6, that are likely radio relics around a compact galaxy group. The authors say these shells may be shock-energised remnants linked to galaxy mergers.
Why the authors say this matters
The authors conclude that at least some odd radio circles (ORCs, large circular radio structures) are shock-energised relics in the outskirts of galaxy groups. They say these may originate during the merger evolution of the brightest group galaxy.
What the researchers tested
The researchers examined 944 MHz radio continuum images from the Australian Square Kilometre Array Pathfinder (ASKAP). They compared the radio shells with the location and properties of the central galaxy, WISEA J184105.19–654753.8, and noted possible matches with non-radio data such as X-ray emission.
What worked and what didn't
Two partial, edge-brightened rings were detected, each about 240 arcseconds across, or roughly 720 kpc. The north-western shell is more prominent and may be associated with an X-ray detection, while the south-eastern shell is weaker and has no counterpart at non-radio wavelengths.
What to keep in mind
The formation scenario is proposed, not proven. The abstract does not describe detailed limitations beyond noting that the shells are likely radio relics and that one shell lacks non-radio confirmation.
Key points
- The paper reports two intersecting radio shells, ORC J1841–6547 (ORC 6), around a compact galaxy group.
- The shells are described as likely radio relics and possible odd radio circles.
- The central galaxy is WISEA J184105.19–654753.8, a radio-bright massive elliptical galaxy with signs of interaction.
- The more prominent north-western shell may be associated with X-ray emission.
- The south-eastern shell has no non-radio counterpart mentioned in the abstract.
Disclosure
- Research title:
- Two radio shells likely trace galaxy merger shocks
- Authors:
- B. Koribalski, Klaus Dolag, Ildar Khabibullin, Ludwig M. Böss, Anna Ivleva, R. P. Norris
- Institutions:
- Australia Telescope National Facility, Western Sydney University, Max Planck Institute for Astrophysics, University of Chicago
- Publication date:
- 2026-04-24
- OpenAlex record:
- View
- Image credit:
- Photo by NASA Hubble Space Telescope on Unsplash · Unsplash License
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