In October 2023, astronomers using the Giant Magellan Telescope Interferometer detected a new, exceptional odd radio circle (ORC), designated ORC J0356–4216. Using the MeerKAT radio telescope, they achieved the exciting discovery. This extraordinary cosmic megastructure displays a striking dueling double-ring pattern. This exceptional feature provides an incredible opportunity to study its performance and intrinsic behavior. This amazing discovery opens a window into the nature of cosmic complexity and how such structures could have formed.
ORC J0356–4216 has a diameter of about two arcminutes, which translates into a physical size of roughly 2.18 million light-years. These dimensions make the ORC one of the most puzzling structures that contradict theories established in modern astronomy. The radio spectropolarimetric observations of ORC J0356–4216 were conducted by researchers from Ruhr University Bochum. For this work, they used both the Australian SKA Pathfinder (ASKAP) and MeerKAT telescopes. Their results were released to the community on the arXiv pre-print server on September 5th. This was an exciting and important breakthrough in the burgeoning field of radio astronomy.
Characteristics and Measurements of ORC J0356–4216
An analysis of our CRORC J0356–4216 observations recently highlighted some of its most exciting characteristics. Their total equipartition magnetic field of the rings were of remarkable magnitudes, 1.82 and 1.65 µG. Together, this points to a surprisingly robust magnetic dominion in this cosmic cavern. Our observations achieved a sensitivity limit to the polarized intensity of the rings of 0.47 mJy. This last degree of polarization ranged from 20 to 30%. These measurements are key in piecing together the magnetic environment around ORC J0356–4216.
The same researchers found the integrated flux density at 943 MHz for both rings to be 4.07 mJy and 2.82 mJy. They additionally determined that at 1.28 GHz, the values decreased to 2.77 mJy and 1.98 mJy. Such data is essential in piecing together how these cosmic formations release energy considerably more than the mass they consume and affect their surrounding environment.
“We present the first radio continuum polarimetry study of a new ORC-like system, which we dub ORC J0356–4216,” – researchers
Understanding the Origins of ORC J0356–4216
All of these factors made it an ideal system for postulating the origins of ORC J0356–4216. Here, researchers posit that the structure’s double-lobed shape and polarization characteristics could indicate the presence of relic emissions from previous active galactic nucleus (AGN) activity or jet-driven outflows. Additionally, WISE colors suggest that the host galaxy is an active galactic nucleus (AGN). This AGN is hosted by an elliptical galaxy.
Sam Taziaux and his colleagues emphasized that “In the case of ORC J0356–4216, the observed double-lobed morphology and polarization characteristics are more readily explained by relic emission from previous AGN activity or jet-driven outflows.” Indeed, this interpretation is consistent with current understanding, but in doing so opens up new questions about formation mechanisms for such features.
Implications for Future Research
The detection of ORC J0356–4216 raises exciting possibilities for future study of these unusual cosmic structures. Astronomers are trying to learn more about these odd radio circles. Research like theirs will provide insight into how these circles are formed and the ways they can be nurtured. The insights gained from ORC J0356–4216 could enhance our understanding of AGN activity, cosmic magnetic fields, and the interplay between different astronomical phenomena.