Astr 222 Feb 9, 2005 

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• Classifying galaxies -- the Hubble sequence

  Elliptical galaxies

  • M87, bright elliptical in Virgo cluster
  • the Leo I dwarf spheroidal galaxy

  Spiral galaxies

  • Local Group galaxy M33 (Sc)
  • NGC 891 -- the Milky Way's "twin"? (Sb)
  • NGC 253
  • NGC 1365 SB
  • NGC 4594, the Sombrero galaxy (Sa)
• Less obvious galaxies

  Irregular galaxies

  • The Large Magellanic Cloud
  • The Small Magellanic Cloud
  • NGC 6822, Local Group Irregular galaxy

  Low Surface Brightness Galaxies

  M101: high surface brightness

  Malin 1: low surface brightness

  UGC 6614: another LSB

  
   

  Physics and the Hubble sequence

  Gas content

  HII regions along the Hubble sequence

  
  Color

  Measures of absolute scale