Free Download of : Active Galactic Nucleus
The term “Active Galactic Nucleus’’ (AGN) refers to the existence of energetic phenomena in the nuclei of galaxies that cannot be attributed directly to stars
• AGN are classified based (in large part) on their luminosity in different wavebands (especially the optical and radio) Seyfert Galaxies
• In 1943, Carl Seyfert identified a class of spiral galaxies w/unusually bright central regions (stellar appearing cores), whose spectra are dominated by high-excitation nuclear emission lines .
Seyfert galaxies make up about 1% of spirals, so there are numerous nearby examples; however, at the time, they were viewed as oddities…..