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Radiative Processes in Astronomy: L18b - The Problem with Scattering

In this lecture we discuss the general problem of scattering when dealing with the radiative transfer equation, illustrating with a two-component sour...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: Lec18a - Photoionization

In this lecture we discuss photoionization a bit further. We show how to obtain the ionization rate and discuss behaviour of (hydrogenic) cross sectio...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L17 - Compton Scattering

This lecture considers Compton scattering as the general case of the low-energy Thomson limit for electron scattering. We obtain the frequency-shift i...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L16b - Thermal Bremsstrahlung

This lecture goes through thermal bremsstrahlung. We start with a derivation in the classical limit, then show how we obtain emission and extinction c...

Radiation Processes in Astronomy

Radiative Processes in Astronomy L16a - Line broadening III, macroscopic velocity fields

This short lecture wraps up the spectral line broadening part by adding some notes on the effects of macroscopic velocity fields, both in the case of...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L15b - line broadening II, collision, Voigt prof, and macroscopic

In this lecture (two parts, here part II) we go through spectral line broadening, focusing mostly on microscopic broadening but discussing also (in th...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L15a - Spectral line broadening I, thermal Doppler and Natural

In this lecture (two parts, here part I) we go through spectral line broadening, focusing mostly on microscopic broadening but discussing also (in par...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L14b - Einsteins atomic coefficients via his original paper

In this lecture we go through Einstein's original paper where he (correctly) suggests the process of stimulated emission. This then also introduces hi...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L14a - Cosmic Background Radiation II, Photosphere of our Universe

In this lecture, part II on teh Cosmic Background Radiation, we calculate and analyze when the era of photon-baryon decoupling occurred and when our U...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L13b - Cosmic Background Radiation I, Era of Recombination

In this application lecture, first of two on the cosmic background radiation, we use knowledge we've acquired in the course to calculate and analyze t...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L13a - Saha and Boltzmann relations

This lecture introduces the Saha and Boltzmann relations to compute excitation and ionisation balance in (local) thermodynamic equilibrium. We also br...

Radiation Processes in Astronomy

Radiative Processes in Astronomy: L12b - Estimate life times of optical and 21cm (hyperfine str) H

This lecture uses semi-classical arguments to make order-of-magnitude scaling estimates for the energies and strengths (life times) of electric dipole...

Radiation Processes in Astronomy