APOD October 19, 2026: NASA Science Explores Treble Clef, an Unusual X-ray and Radio Source
A structure named Treble Clef
The radio structure called Treble Clef extends over 2 million light-years. Its shape resembles a familiar musical symbol, while the Milky Way Galaxy hides its visible light. The object is also known as VLSS J0318.9+5755. Its nature remained unknown when it was examined in 2004.
Observations suggest an origin
Recent observations by the Chandra X-ray Observatory and eROSITA have led to a hypothesis about Treble Clef’s history. The central cloud of charged particles may originally have been expelled by a supermassive black hole at a galaxy’s center.
After the particles’ radio emission faded, a shock wave may have reinvigorated them. The proposed shock wave came from a collision between two galaxy clusters.
Radio and X-ray emissions
The featured composite image marks radio emission in red and recently discovered X-rays in blue. It brings together the different emissions detected from Treble Clef. NASA describes unusual objects such as Treble Clef as sources of unexpected clues about the cosmos. The observations have prompted a possible explanation for how the structure’s particles became energized again.
Key points
- Treble Clef’s radio structure spans more than 2 million light-years.
- The Milky Way hides the structure’s visible light.
- Chandra and eROSITA observations support a hypothesis involving a black hole and a shock wave.
- The composite image shows radio emission in red and X-rays in blue.