Astronomers have identified a new type of cosmic structure called an odd radio circle (ORC), which features two intersecting rings of radio emission only visible in radio wavelengths, with this being only the second such case observed.

This discovery was made using LOFAR, a European low-frequency radio telescope, in collaboration with the citizen science network RAD@home, marking the first ORC found through LOFAR and citizen science efforts.

LOFAR's advanced array of antennas acts as a large interferometer, enabling deep observations of cosmic history that led to the detection of this ORC and two other enormous radio galaxies, each spanning over a million light-years.

The most distant and powerful ORC discovered to date is designated RAD J131346.9+500320, located at nearly redshift 0.94, which means it is seen as it was when the universe was about half its current age.

Additional discoveries include two large cosmic structures: RAD J122622.6+640622, a galaxy over 25 times the size of the Milky Way with a bent jet forming a large radio ring, and RAD J142004.0+621715, which exhibits a ring of radio emission at the end of one jet, both situated within dense galaxy clusters.

All three structures are found within dense galaxy clusters with masses around 100 trillion times that of the Sun, where interactions between jets and hot plasma are believed to shape these features, suggesting they are part of a broader family of plasma structures influenced by black hole activity.

Researchers propose that these rings may form from superwind outflows originating from spiral host galaxies, rather than from shockwaves caused by black hole or galaxy mergers, offering new insights into galaxy and black hole co-evolution.

Future observatories like the Square Kilometre Array (SKA), along with optical surveys such as DESI and LSST, are expected to discover many more ORCs, which will help scientists understand their formation and evolution.

The findings highlight the role of citizen scientists in modern astronomy and suggest that upcoming telescopes and surveys will significantly enhance our understanding of these exotic plasma structures and their origins.

These structures support the idea that interactions between relativistic plasma jets from black holes and their environment shape such rings, indicating they are part of a broader family of cosmic plasma phenomena.