ASTRONOMICAL SPECTROSCOPY

1) A brief introduction to spectroscopy as observational technique.
2) Characteristics of emission-line spectra: gaseous nebulae, Novae, Supernovae, Supernova remnants, star forming regions, active galactic nuclei.
3) The Boltzmann and the Saha equations.
4) The Radiative Transport Equation. The Equivalent Thermodynamic Equilibrium. Radiation density. Radiation transport in the lines. Deviations from thermodynamic equilibrium.
5) The cross-section of collisional interactions. The collisional efficiency rate.
6) Study of the population ratio in a two-level system. The two-level system in the optical range. Conditions for the emission of forbidden lines. The two-level system at radio frequencies. The H I 21 cm and the CO 2.6 mm lines. Line intensity as a function of density and temperature. Determination of the gas density and temperature.
7) Recombination lines. Population of the levels. Intensity of the optical recombination lines of H I. Intensity of the radio recombination lines.
8) Sources of continuous emission and absorption. Free-free transitions of thermal electrons. The thermal radio continuum. The synchrotron continuum. Bound-free and free-bound transitions in the optical-UV. Continuum emission from recombination. The 2-photons emission.
9) Statistical equilibrium in ionized nebulae. Radiative ionization and recombination. Ionization equilibrium in H II regions. The Stroemgren sphere. Stratification of ionization. H I regions. Cold dense and hot tenuous neutral cloud. Photoionization heating in H II regions. Cooling from metastable level transitions. Thermal equilibrium in H II regions.
10) Extinction by dust grains.