What is Radio galaxy?
[[File:Centauros a-spc.png|thumb|300px|The false-colour image of the nearby radio galaxy [[Centaurus A]]. <br/>It shows [[radio]] (red), 24-micrometre [[infrared]] (green) and 0.5-5 [[keV]] [[X-ray]] emission (blue). The jet emits [[synchrotron radiation]] in all three wavebands: <br/>{{•}} The red lobes only emit in the radio frequency range <br/>{{•}} Gas and dust in the galaxy emits [[thermal radiation]] in the [[infrared]] <br/>{{•}} Thermal [[X-ray]] radiation from hot gas relativistic [[electrons]] causes the blue 'shells' around the lobes to the south (bottom)]] '''Radio galaxies''' and their relatives, radio-loud [[quasar]]s and [[blazar]]s, are types of [[active galactic nucleus|active galaxy]] that are very luminous at [[radio waves|radio wavelengths]]. They have luminosities up to 10<sup>39</sup> [[watt|W]] between 10&nbsp;MHz and 100&nbsp;GHz.<ref>[http://ned.ipac.caltech.edu/level5/Glossary/Essay_fanaroff.html Fanaroff-Riley classification]</ref> The radio emission is due to the [[synchrotron|synchrotron process]]. The observed structure in radio emission is determined by the interaction between twin [[relativistic jet|jets]] and the external medium, modified by the effects of [[relativistic beaming]].<ref>Relativistic jets, relatavistic beaming, relatavistic electrons = radiation and particles moving at speeds which are close to the [[speed of light]].</ref> Radio galaxies are almost exclusively large [[elliptical galaxy|elliptical galaxies]]. ''Radio-loud'' active galaxies can be detected at large distances, making them valuable tools for observation. Recently, much work has been done on the effects of these objects on the [[intergalactic medium]], particularly in [[galaxy cluster|galaxy groups and clusters]]. == References == {{reflist}} {{-}} {{science-stub}} [[Category:Galaxies]]