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Stunning double-ring ORC discovered across cosmic time
Astronomers working with citizen scientists have identified an extraordinary odd radio circle (ORC) — a dual-ring system so powerful and distant it may rewrite parts of our understanding of how black holes shape their galactic environments. Catalogued as J131346.9+500320, the object lies so far away that its radio emission has traveled about 7.7 billion years to reach Earth. Unlike most ORCs, which show a single circular radio structure, this source displays two intersecting rings of bright radio emission, each roughly 978,000 light-years across and surrounded by a faint halo extending about 2.6 million light-years.
ORCs are rare, large, circular regions of radio light detected in deep radio surveys. They emit predominantly in radio wavelengths and lack strong counterparts at optical wavelengths, making them enigmatic targets for radio astronomers. The discovery of a double-ring ORC is particularly significant because it provides new observational constraints on the physical mechanisms that generate these structures and on the role of supermassive black holes in driving large-scale energetic phenomena.
What likely produced the double rings?
Current evidence points to powerful black hole-driven processes as the most plausible explanations. Supermassive black holes can generate enormous jets of relativistic plasma and drive energetic winds into surrounding gas. Over time, these outflows inflate radio lobes — extended regions filled with synchrotron-emitting electrons spiraling in magnetic fields. The team led by Ananda Hota (University of Mumbai) and collaborators from the RAD@home citizen science project suggests that J131346.9+500320’s twin rings were shaped when a powerful bipolar outflow or shockwave intersected relic radio lobes.
If a galaxy experienced a major disturbance — such as a merger with another galaxy or an episode of renewed black hole activity — a large-scale shock or superwind could compress and re-energize aged, fading synchrotron plasma. That reacceleration can temporarily brighten the relic emission and produce ring-like or shell-like morphologies. In the case of J131346.9+500320, the geometry and spectral properties imply old synchrotron radiation whose glow has been revived by a later, energetic event: a fossil radio structure refreshed by new winds or shocks.
Scientific context and background
Synchrotron radiation is the main mechanism behind most radio emission in these sources. Relativistic electrons accelerated by shocks or magnetic reconnection spiral along magnetic fields and emit broadband radio waves. ORCs stand out because they are unusually circular and extended, often exceeding the size of their host galaxy by orders of magnitude. Many ORCs are found close to galaxies that host supermassive black holes, strengthening the connection between black hole feedback and radio structures such as jets, lobes, rings, and bubbles.
There are only a few dozen confirmed ORCs so far; only a small subset show multiple ring structures. Finding a powerful double-ring ORC like J131346.9+500320 strengthens the idea that ORCs are part of a broader family of black hole-driven plasma phenomena rather than isolated curiosities. The discovery also illustrates how human visual inspection — in this case, the RAD@home citizen science collaboration working with professional astronomers — remains invaluable for pattern recognition tasks in large radio surveys.
Related discoveries and implications
The researchers also report two additional systems that reinforce the black hole connection: RAD J122622.6+640622, a radio galaxy with a bent jet that terminates in a large radio circle, and RAD J142004.0+621715, which similarly shows a radio circle at the end of a jet. Taken together, these objects indicate multiple ways that black hole jets, winds, and environmental shocks can produce ring-like radio morphologies.
Understanding ORCs has broader implications for galaxy evolution. Black hole feedback — the energy injected into a galaxy’s gas by jets and winds — regulates star formation, gas cooling, and the growth of the black hole itself. ORCs may therefore be fossil records of powerful feedback episodes that shaped their host galaxies billions of years ago. Identifying the physical conditions that create ORCs helps us map how energy is transported across intergalactic scales and how galaxies and their central black holes co-evolve.
Observational methods and future prospects
Detecting ORCs relies on deep radio imaging and careful inspection of survey datasets. Combining multiwavelength follow-up (radio spectral analysis, optical spectroscopy to get redshifts, and X-ray imaging for hot gas) will be essential to pin down ages, energetics, and the exact drivers of each system. Future radio facilities and continued analysis of archival survey data, aided by citizen science and machine learning, should expand the ORC sample and clarify their diversity.
Expert Insight
"Discoveries like J131346.9+500320 give us luminous fossils to probe black hole activity across cosmic time," says Dr. Leila Morgan, an observational radio astronomer (fictional). "By measuring the ring sizes, spectral aging of the radio plasma, and the surrounding gas conditions, we can reconstruct the timing and power of past feedback events. That helps tie black hole growth to the evolutionary history of galaxies."
Conclusion
J131346.9+500320 stands out as the most powerful and distant double-ring ORC identified so far, offering concrete evidence that supermassive black hole activity — through jets, shocks, or superwinds — can create and later re-energize large circular radio structures. As radio surveys deepen and the catalog of ORCs grows, these unusual radio rings will serve as important signposts of past energetic episodes that sculpt galaxies and their environments across billions of years.
Source: scitechdaily
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