Key facts
- On Oct. 14, 2026, NASA's Chandra X-ray Observatory captured an image showing a radio wave formation that resembles a treble clef.
- The black‑hole outburst drives charged particles and magnetic fields outward at near‑light speed, producing bright radio waves that fade as particles lose energy.
- Later, the collision of the two galaxy clusters compresses or re‑energizes the particle‑magnetic cloud, causing the radio emission to brighten again.
- Shock waves from the cluster collision, similar to sonic booms from supersonic jets, may have helped re‑energize the radio‑emitting cloud.
NASA Science reported that on Oct. 14, 2026, NASA’s Chandra X-ray Observatory captured an image showing a radio wave formation resembling a treble clef.
It lies behind the Milky Way’s plane, where the Treble Clef is usually hidden by interstellar matter, yet X‑ray and radio observations penetrate the obscuration. Researchers say the shape results from a supermassive black hole outburst and a later galaxy‑cluster collision that re‑energized the radio cloud. Researchers nicknamed the formation the “Treble Clef” because its shape strongly resembles the musical symbol.
Observers see a familiar shape in the radio data without any physical connection to music, a phenomenon described as pareidolia. The black‑hole outburst propels charged particles and magnetic fields outward at speeds approaching that of light, creating bright radio emission that gradually fades as the particles lose their energy. Later, the collision of the two galaxy clusters squeezes or re‑energizes the particle‑magnetic cloud, which causes the radio emission to brighten again.
Shock waves produced by the cluster collision, comparable to sonic booms from supersonic jets, may have contributed to re‑energizing the radio‑emitting cloud. X‑ray measurements from Chandra and eROSITA reveal diffuse gas at the location with temperatures of many millions of degrees, indicating that a galaxy cluster hosts the object. When researchers subtract a symmetric oval X‑ray model from the data, excess emission remains brightest to the left and right of the cluster center and faintest in the middle.
The pattern of this residual excess shows that the merger proceeded along a left‑to‑right axis, with the direct impact estimated to have occurred a few hundred million years ago. After the collision the two galaxy clusters are now drifting apart from each other. The composite image displays Chandra and eROSITA X‑rays in blue, LOFAR radio emission in red, and infrared light from the United Kingdom Infrared Telescope in white.
Andrea Botteon of the National Institute for Astrophysics (INAF) in Italy led the study of the Treble Clef that appeared in the journal Astronomy & Astrophysics. NASA’s Marshall Space Flight Center in Huntsville, Alabama manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X‑ray Center conducts science operations from Cambridge, Massachusetts and flight operations from Burlington, Massachusetts.
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