seyfert-galaxy

Seyfert galaxy

[sahy-fert, see-]
noun Astronomy.
one of a group of spiral galaxies with compact, bright nuclei having characteristically broad emission lines suggestive of very hot gases in violent motion at the center.

Origin:
1965–70; named after Carl K. Seyfert (1911–60), American astronomer, who first described them

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World English Dictionary
Seyfert galaxy (ˈsaɪfət)
 
n
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 & Unabridged 10th Edition
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American Heritage
Science Dictionary
Seyfert galaxy  [%PREMIUM_LINK%]     (sē'fərt, sī'-)  Pronunciation Key 
A spiral galaxy with a small, compact, bright nucleus that exhibits variable light intensity and radio-wave emission. Seyfert galaxies are active galaxies and are thought to contain a black hole in their galactic nucleus. The nuclei of Seyfert galaxies generate an emission spectrum characteristic of hot, ionized clouds of gas, shooting out from the accretion disk around the black hole. The observations during the 1940s of American astronomer Carl Seyfert (1911-60), after whom the galaxies are named, demonstrated that these jets of gas are expelled from the nucleus at speeds up to millions of miles per hour. See also blazar, quasar.

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