Astronomers have identified the most powerful and distant odd radio circle ever seen, a colossal deep-sky object featuring a rare double-ring structure. The discovery, made by a collaboration of professional researchers and citizen scientists, provides the strongest evidence yet that these enigmatic cosmic structures are forged by powerful outflows from the supermassive black holes at the centers of galaxies. The object, cataloged as RAD J131346.9+500320, is so remote that its light traveled for billions of years to reach Earth, offering a glimpse into a time when the universe was just half its current age.
Odd radio circles, or ORCs, are a recently identified astronomical phenomenon, first detected only six years ago. These immense, faint rings of radio emissions are invisible in the optical spectrum and can span areas of space far larger than entire galaxies. Only a small number have been confirmed, and their origin has remained a topic of intense debate. This new finding challenges previous theories involving cataclysmic black hole mergers and instead points toward energetic processes within a single host galaxy. The unique dual-ring formation and extreme energy of this particular ORC offer a crucial test case for understanding the lifecycle of galaxies and the far-reaching influence of their central black holes.
A New Record-Holding Cosmic Circle
The discovery of RAD J131346.9+500320 sets new benchmarks for this class of celestial object. Its location at a redshift of approximately 0.94 makes it the most distant ORC ever confirmed, providing a valuable window into the universe’s past. This distance also establishes it as the most intrinsically powerful and energetic odd radio circle observed. Its composition is as remarkable as its power; it is only the second ORC found to possess two distinct, intersecting rings. This complex structure provides astronomers with more detailed information than a simple, single ring, allowing them to better probe the underlying physics of its creation.
The scale of the object is immense. Each of the two primary rings measures nearly one million light-years in diameter, making them many times larger than our own Milky Way galaxy. Surrounding this double structure is a fainter, more diffuse halo of radio emissions that extends across 2.6 million light-years of intergalactic space. These structures are composed of relativistic, magnetized plasma, the same kind of matter that makes up powerful jets ejected from black holes. The light signature suggests it is old synchrotron radiation, indicating that the event that created the rings happened long ago, with the structure now seen as a glowing “fossil relic” of past galactic activity.
Citizen Science and Advanced Telescopes
This landmark discovery was not made by a single astronomer but by a large, collaborative effort that highlights a modern approach to scientific investigation. The RAD@home Astronomy Collaboratory, a citizen science platform founded by Dr. Ananda Hota of the University of Mumbai, was instrumental in identifying the object. This marks the first time an odd radio circle has been discovered through a citizen science initiative. Volunteers and professional astronomers worked together to analyze vast amounts of data, demonstrating the continued importance of human pattern recognition in an era increasingly dominated by automated algorithms.
The Power of LOFAR
The data itself came from one of the world’s most advanced radio telescopes, the Low-Frequency Array (LOFAR). LOFAR is a cutting-edge, pan-European observatory that combines signals from tens of thousands of antennas distributed across the Netherlands and partner countries. Operating as a single, enormous interferometer, it provides an exceptionally sharp and sensitive view of the sky at low radio frequencies. This capability is crucial for detecting faint, diffuse structures like ORCs that are invisible to other telescopes. The discovery of RAD J131346.9+500320 is the first of its kind attributed to LOFAR, showcasing the telescope’s power to uncover previously unknown cosmic phenomena.
Galactic Superwinds as a Leading Theory
The detailed observations of this record-breaking ORC are reshaping scientific understanding of how these structures form. While several theories have been proposed since ORCs were first discovered, the evidence from RAD J131346.9+500320 strongly favors one particular model: galactic superwinds. This theory posits that the rings are giant shockwaves expanding outward from a central galaxy. These powerful winds are driven by either a period of intense star formation—a starburst—or by energy released from an active galactic nucleus, where a supermassive black hole is actively consuming matter.
This model stands in contrast to earlier hypotheses, such as the idea that ORCs are the spherical remnants of two colliding supermassive black holes. The characteristics of this dual-ringed object, along with other similar structures, align more closely with outflows from a single, highly active galaxy. The immense energy required to power such a large structure over millions of years is consistent with the sustained output from a galactic nucleus. The radio emissions are likely generated as the expanding shockwave collides with and energizes the tenuous gas in the intergalactic medium surrounding the host galaxy.
A Broader Family of Cosmic Structures
Further strengthening the galactic outflow theory, the same research effort that identified the new ORC also uncovered two other unusual and enormous radio galaxies. One of these, RAD J122622.6+640622, is a giant galaxy nearly three million light-years across—more than 25 times the size of the Milky Way. One of its powerful plasma jets appears to make an abrupt sideways bend before terminating in a spectacular radio ring roughly 100,000 light-years wide. Another object, RAD J142004.0+621715, also shows a clear connection between its radio jets and a large ring structure.
These related discoveries suggest that odd radio circles are not isolated curiosities but are part of a larger family of exotic plasma structures found throughout the universe. They appear to be a natural, though perhaps rare, outcome of the interaction between powerful black hole jets, galactic winds, and the complex environments within dense galaxy clusters. These findings provide a new framework for understanding how galaxies and their central black holes co-evolve, influencing each other and shaping the cosmic structures around them on vast scales. Future observations with next-generation radio telescopes will continue to probe these bizarre and beautiful objects, seeking to definitively solve the mystery of their origins.
