Seyfert galaxy

The Seyfert galaxies are galaxies which features having a bright central stellar core point, around 1036 to 1038 W, and a spectrum showing emission lines that are of high ionization. The Seyfert galaxies are named after Carl Seyfert, who discovered them in 1943.

Types
Based on its spectrum, Seyfert galaxies are classified as type 1 or 2. Galaxies of type 1 has both lines allowed as H, He I and He II and narrower forbidden lines as for instance O III. In type 1 permitted lines are much broader than the forbidden lines (equivalent to a velocity of 104 km/s−1 ) whereas type 2 are similar and narrower (< 103 km/s−1). Seyferts galaxies of type 1 have spectra very similar to quasars.