Galactic Rotation

• measuring speeds: Doppler effect
• circular orbits, relative velocity; sketch of geometry
  reminder of coordinate conventions and sky view
• gas rotation kinematics
  • H I 21 cm emission: velocity distribution in the Galactic midplane
  • molecular CO emission: velocity distribution plot (Dame, Hartmann, and Thaddeus 2001)
• stars: proper motions
• Oort's constants
• Galactic rotation curve