| Term: | Radio galaxies |
| Definition: |
A galaxy that is extremely luminous at radio wavelengths between 10 MHz and 100 GHz. The radio luminosity of a strong radio galaxy (10^37 - 10^39 watts) can be up to a million times greater than the radio output of an ordinary galaxy and up to a hundred times greater than the optical luminosity of a galaxy such as the Milky Way. The optical counterparts of radio galaxies are usually an elliptical galaxy. Radio galaxies often exhibit jet structure from a compact nucleus. They typically display two radio lobes that are often approximately aligned with the jets observed in the optical and that may extend for millions of light-years. |