Astro*Dictionary
by Michael Erlewine

1 article for
"Seyfert Galaxies"

A small class of spiral galaxies that have very small, intensely bright nuclei whose broad spectral emission lines indicate that the atoms present are in a very high state of activity. They are powerful sources of radio energy, and also of ultraviolet and infrared radiation.

 

See also: ♦ Galaxy ♦ Electromagnetic Spectrum