Cygnus A


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Cygnus A

An intense radio source in Cygnus that has a flux density at 178 megahertz of 8100 jansky. It is a typical double radio source (see illustration at radio-source structure) and is identified with a 16-magnitude radio galaxy; a narrow radio jet connects the central galaxy to the NW lobe. The galaxy has a redshift of 0.057, indicating a distance of about 230 megaparsecs, and a spectral index of –0.8 below 1 GHz. It is the brightest low-redshift radio source, with a radio luminosity more typical of very distant radio galaxies (those above a redshift of one).

The galaxy is at the center of a cooling flow cluster (see clusters of galaxies), and its optical spectrum is rich in forbidden emission lines. It also contains a polarized blue continuum that is due to scattered light from a hidden quasar nucleus.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Cygnus A

[′sig·nəs ′ā]
(astronomy)
A strong, discrete radio source in the constellation Cygnus, associated with two spiral galaxies in collision.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The (https://public.nrao.edu/news/vla-reveals-new-object/) National Radio Astronomy Observatory  said the bright object was not in the Cygnus A galaxy when the Very Large Array last viewed it in 1996.
(http://chandra.harvard.edu/press/00_releases/press_110600cyg.html) Cygnus A  is known for being one of the greatest sources of radio waves in space, and the closest one to Earth that is so active on that side of the electromagnetic spectrum.
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She and her colleagues analyzed the spectra of ultraviolet light recorded by the Hubble Space Telescope to confirm that a quasar lies at the center of Cygnus A, the brightest radio galaxy in the northern sky.
The group focused special attention on Cygnus A, the brightest radio galaxy in the northern sky.
According to Djorgovski, this all but proves that the core of Cygnus A harbors a quasar.
This newest innovation showcases Cygnus as a future testbed for various types of hosted payload missions.
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