Seyfert galaxy

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Sey·fert galaxy

 (sē′fərt, sī′-)
n.
A spiral galaxy having a small, compact nucleus many times brighter than the rest of the galaxy and exhibiting variable light intensity and radio emission. Seyfert galaxies are active galaxies thought to be powered by the accretion of material onto black holes in their galactic nuclei.

[After Carl Keenan Seyfert (1911-1960), American astronomer.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Seyfert galaxy

(ˈsaɪfət)
n
(Celestial Objects) any of a class of spiral galaxies having a very bright nucleus, possibly corresponding to an active period in the lives of all spiral galaxies
[C20: named after Carl K. Seyfert (died 1960), US astronomer]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
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References in periodicals archive
Even if it's the closest and brightest Seyfert galaxy, we don't see M77's core as extraordinarily bright as a quasar's for two reasons, though: Its black hole isn't consuming enough matter, and its beamed outflow jet isn't pointed directly at us.
This object lies more than one billion light years away in the direction of the constellation Coma Berenices, and is a Seyfert galaxy, characterised by a very bright AGN resulting from the presence of the massive black hole at its nucleus.
It is known as a type II Seyfert galaxy, characterised by its dazzling nucleus.
E-VLBI was recently used to observe a Seyfert galaxy emitting powerful gamma rays thought only to originate from the most powerful type of black holes.
Dr Hewitt finally pointed out two deep sky objects to look for near Jupiter, both in Cetus: NGC 246, a planetary nebula, and Messier 77, the brightest Seyfert galaxy, which contains the Cetus A radio source, thought to be a supermassive black hole.
Scientists classify NGC 4945 as a Seyfert galaxy after the American astronomer Carl K.
General topics include optical variability, including long-term optical quasar variability, IR variability, including the correlation of near infrared and optical variability on NGC 4151, x-ray variability, including the relationship between optical and x-ray variability in Seyfert galaxies, radio variability, including 3C 120 and the disk-jet connection, blazars, including photometric and polarimetric observations of BL Lac objects in the optical region, including flows and shocks in Seyfert Galaxy nuclei and general considerations, including closing thoughts on AGN variability by the conference chair.
Now, for a taste of winter galaxy hunting, dive deep into the celestial sea to fish out M77, a 9th-magnitude Seyfert galaxy conveniently located 1[degrees] southeast of 4th-magnitude Delta ([delta]) Ceti.
A Seyfert galaxy,also photographed by the Liverpool Telescope last week, is thought to contain a black hole which produces vast amounts of energy as it swallows surrounding stars, dust and gas.
NGC 5548 is a Seyfert galaxy, one of a class that harbors what astronomers call an "active galactic nucleus." Such a galaxy contains an extremely compact object--possibly a massive black hole--that feeds on the rest of the galaxy.
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