radio galaxy
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radio galaxy
A galaxy that is extremely luminous at radio wavelengths. It is usually a giant elliptical—the largest galaxy in a cluster. The radiation emission may come only from the nucleus, but more typically also comes from a pair of more or less symmetric lobes stretching as far as a million light-years either side of the nucleus. Many radio galaxies also show emission from jets connecting the nucleus to these lobes. Whatever produces the radio emission must have a long “memory,” preserving its direction over millions of years. The only reasonable explanation for the central energy source, as in the case of all active galactic nuclei, is a supermassive black hole, that squirts matter out along its spin axis and so delivers a steady supply of energy to the lobes. Among the brightest radio galaxies are Centaurus A, Cygnus A, and Virgo A (see M87).
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categories related to 'radio galaxy'
- Celestial Bodies - radio galaxy: galaxy that emits stronger-than-normal radio waves
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American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
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Wiley Book of Astronomy
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Mentioned in
Virgo A
(astronomy)
core-halo galaxy
(astronomy)
db galaxy
(astronomy)
Centaurus
(constellation)
Sagittarius B2
(astronomy)
» More