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.
Gamma-Ray Quasars
Explanation: Gamma rays are more than 10,000 times more energetic than visible light. If you could “see” gamma rays , the night sky would seem very different indeed. The bright object in the center of the false color gamma-ray image above is quasar 3C279, a nondescript, faint, starlike object in the visible sky. Yet, in June of 1991 a gamma-ray telescope onboard NASA's orbiting Compton Gamma Ray Observatory unexpectedly discovered that it was one of the brightest objects in the gamma-ray sky. Shortly after this image was recorded the quasar faded from view at gamma-ray energies. Astronomers are still trying to understand what causes these enigmatic objects to flare so violently. Another quasar, 3C273, is faintly visible above and to the right of center.
| Date | October 23, 1995 |
|---|---|
| Credit | Credit: NASA, CGRO, EGRET team. |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |



