Molecular Content of Galaxies

• 1. How to observe the H2 component?
  why cold H2 molecule is invisible.
  Infrared H2 lines, UV H2 absorption lines
  CO tracer. Isotopes. Virial conditions.
  CO/H2 conversion ratio
• 2. Molecular component of the Milky Way
  Molecular surveys, distances, mapping
  Spiral arms structure and contrast
  Clumpiness of molecular clouds
• 3. H2 in external galaxies
  Statistical properties, comparison with HI gas and other tracers.
  Relation to star formation
  Dynamics: spiral structure, warps,
  polar rings, shells, etc..
• 4. Molecules in absorption
  in our MW, in intervening galaxies in front of QSO
  Physics, chemistry, evolution as a function of z
  Variation of fine-structure constant alpha
• Observations proposed
  Absorption in front of PKS1830-211, HCO+(2-1), H13CO+(2-1), (3-2),
  and measurement of T(CMB) at z ~ 1