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.
Any of a number of spiral galaxies with a small, intensely bright nucleus and a spectrum with strong, broad spectral lines.
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.
Origin of seyfert-galaxy
- After Carl Keenan Seyfert (1911–1960), American astronomer
From American Heritage Dictionary of the English Language, 5th Edition