Point Sources in Front of CMB: SPT

The Atomic Age

• microphysics: recombination of hydrogen (mostly)
  • ionized (plasma) to neutral (gas)
  • opaque to transparent

The Physics of the CMB

• Saha and equilibrium ionization
• recombination
  CMB spectra distortion from line emission: in context
• last scattering
• freeze-in of residual ionization
• gas decoupling