Seyfert galaxy vs galaxy

Seyfert galaxy

galaxy

noun
  • An assemblage of things or people seen as luminous or brilliant. 

  • Any of the collections of many millions or billions of stars, galactic dust, black holes, etc. existing as independent and coherent systems, of which there are billions in the known universe. 

  • Any print or pattern reminiscent of a galaxy, generally consisting of blending, semiopaque patches of vibrant color on a dark background. 

verb
  • To furnish with galaxies. 

How often have the words Seyfert galaxy and galaxy occurred in a corpus of books? (source: Google Ngram Viewer )