3 articles · Updated · Down To Earth Magazine · Jun 23
Summary
Monthly Notices of the Royal Astronomical Society published the discovery of BAARG, a bow-and-arrow-shaped radio galaxy first spotted by a volunteer during a 24 May 2025 RAD@home online class.
560,000 light-years across on one side, BAARG shows a broad radio arc and an S-shaped tail that researchers say had not been clearly seen before in radio observations.
1,000 to 3,500 kilometers per second is the estimated speed of the galaxy through hot cluster gas, a supersonic plunge thought to create a bow shock that compresses one jet and bends the other.
Machine-learning systems had catalogued BAARG as an ordinary giant radio galaxy, but the human observer recognized the unusual morphology across datasets.
Future surveys from the Square Kilometre Array could uncover more such objects, using distorted radio jets to map otherwise invisible pressure gradients and shock boundaries in galaxy clusters.
The discovery of RAD-BAARG, a unique cosmic entity identified by citizen scientist Pranim Limbo through the RAD@home project using LOFAR survey images, highlights the power of collaborative research. Limbo’s work shows how motivated individuals can make significant contributions to astronomy. The findings, published in June 2026, quickly brought RAD-BAARG into the spotlight for its distinctive arc-shaped morphology, which provides the first direct radio imaging of such a feature. This breakthrough offers new insights into cosmic interactions and demonstrates the growing impact of citizen science in advancing our understanding of the universe.