APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Treble Clef: Unusual X-ray Hot Radio Source
Explanation: Explanation : What is Treble Clef? This unusual radio structure extends over 2 million light-years and resembles a common musical symbol — but has its visible light hidden by our own Milky Way Galaxy. Examined in 2004, the nature of VLSS J0318.9+5755, dubbed Treble Clef, remained unknown. Recent observations by the Chandra X-ray Observatory and eROSITA, however, have led to the hypothesis that the Treble Clef central cloud of charged particles was originally expelled by a supermassive black hole at the center of a galaxy. After the radio emission from those particles faded, they may have been reinvigorated by a shock wave from the collision of two clusters of galaxies. The featured composite image shows radio emission in red, while recently discovered X-rays are shown in blue. Unusual objects like Treble Clef give humanity unexpected clues about how whole clusters of galaxies interact as well as the general evolution of our universe.
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Tomorrow’s picture: backwards rainbow
| Date: | October 19, 2026 |
|---|---|
| Credit: | X-ray: NASA/CXC/INAF-IRA/A. Botteon et al.; Infrared: UKIDSS–GPS; Radio: ASTRONLOFAR; Image processing: NASA/CXC/SAO/N. Wolk |
| Authors & editors: | Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti, Keighley Rockcliffe |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |