Astronomers led by Andrea Botteon from the Italian National Institute for Astrophysics have identified the nature of the radio source VLSS J0318.9+5755. Known as the Treble Clef, the object is located 1.5 billion light-years from Earth behind the Milky Way's dust disk. It is classified as a radio phoenix, a remnant of ancient supermassive black hole activity.
The structure spans 2.5 million light-years and consists of plasma reheated by shock waves from colliding galaxy clusters. Researchers estimate the age of the revived emission at 190–200 million years. Data for the study came from the LOFAR array, the GMRT telescope, the Chandra X-ray Observatory, and the SRG/eROSITA satellite.
The object was first detected in the 1960s but was previously misidentified as a pulsar or an artifact due to its position near the galactic plane. A connection to a galaxy cluster was hypothesized in 2004, but detailed confirmation required modern multi-wavelength surveys. The findings are accepted for publication in Astronomy & Astrophysics.
