Concept information
Terme préférentiel
Seyfert galaxy
Définition(s)
- A Seyfert galaxy is galaxy with a small, intensely bright nucleus which shows strong, broad emission lines. Seyfert galaxies, named after Carl Seyfert (1911–1960), who first defined them as a group of similar objects in 1943, are nearly all spiral galaxies or barred spirals. Two distinct classes were identified by Ed Khachikian and Daniel Weedman on the basis of their emission lines. Class 1 Seyferts, such as NGC 5548, show broadening only of their hydrogen lines – those that can be associated with the highest gas densities. Class 2 Seyferts, such as NGC 1068 (the brightest known Seyfert), show broadening of all their lines. In both cases, the spectrum points to the presence of large amounts of very hot, fast-moving gas close to the galactic center that is being prevented from escaping by a large central mass. (Encyclopedia of Science, by David Darling, https://www.daviddarling.info/encyclopedia/S/Seyfert_galaxy.html)
Concept(s) générique(s)
Concept(s) spécifique(s)
Traductions
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français
URI
http://data.loterre.fr/ark:/67375/MDL-JPPZNTGZ-7
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