Citizen scientist Pranim Limbo discovered the RAD-Bow-And-Arrow Radio Galaxy (RAD-BAARG) through the RAD@home Astronomy Collaboratory. A paper describing the galaxy was published in the journal Monthly Notices of the Royal Astronomical Society on June 22, 2026.

The discovery utilized ultrasensitive radio images from the LOFAR Two-metre Sky Survey. The image of the RAD-BAARG combines radio emission data from the LOFAR telescope with optical data from the Beijing-Ariza Sky Survey. The RAD-BAARG is located approximately 2 billion light-years from Earth and is classified as a Giant Radio Galaxy.

Ananda Hota, principal investigator of the RAD@home Astronomy Collaboratory and the first author of the paper, commented on the galaxy's unusual shape. "The structure of this source is unlike that of any radio galaxy I have seen in the last 25 years," Hota said.

One of RAD-BAARG's jets bends into a bow shape after encountering a shock front in the surrounding gas. This bow-like structure extends approximately 1.8 million light-years across. The opposite jet twists into a distorted S shape and then fades into a faint tail, forming an arrow shape. The galaxy has a total length of approximately 2.3 million light-years.

RAD-BAARG appears to be falling toward a nearby cluster of galaxies. This movement occurs through the intracluster medium, which is the hot, diffuse gas found between galaxies in a cluster.

Why It Matters

The discovery of the RAD-Bow-And-Arrow Radio Galaxy by a citizen scientist demonstrates the contributions that public participation can make to astronomical research. The unique structure and immense size of RAD-BAARG, a Giant Radio Galaxy, offer new data points for studying the dynamics of galaxies interacting within cosmic environments. The bowing and twisting of its jets provide observable evidence of its interaction with the intracluster medium as it moves towards a galaxy cluster.