Astronomy Picture of the Day

Discover the cosmos! Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer.

September 30, 1995

An Energetic Radio Galaxy
Credit: NASA, NRAO, VLA, HST, WFPC 2, M. Longair (U. Cambridge)

Explanation: The radio and optical emission seen in the above superposed images of the radio galaxy 3C368 indicate that energetic processes are at work. A radio galaxy is a galaxy that is visible to radio telescopes. A large radio signal usually indicates very powerful phenomena. The optical light is shown above in red and the radio emission in blue contours. Currently, one can only guess what causes the unusual radio and optical features. Scientists working with the Hubble Space Telescope speculate that the radio emission might have resulted from jets of high-velocity material thrown off from the center of the galaxy, while the optical light comes from gas and dust that are remnants of a burst of star formation triggered by the radio jet.

Tomorrow's picture: Central Galactic Star Bursts

Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
A service of: LHEA at NASA/ GSFC