Practical Astrophysical Spectroscopy

Lecturer: Dr. Brian Espey Rationale:

This course provides a link between theoretical calculations and practical solution of diagnostic measurement of astrophysical plasmas covering a wide range of density and temperature

Module Aims:

Starting with assumptions of thermodynamic equilibrium (TE) and statistical physics, diagnostics are developed to probe such material. The extension to conditions of local thermodynamic equilibrium (LTE) and to some non-LTE situations will enable the student to obtain quantitative information for plasmas in a general astrophysical context. This is a graduate level course suitable for early-stage astrophysics students, but may also be of interest to general physics students. Some experience in computer codes (C++, IDL or Python) would be of benefit.

Module Learning Outcomes: On successful completion of this module, students will be able to:
  1. Deconstruct a practical problem to identify which diagnostics are appropriate to use (e.g., whether a gas is dominated by collisional or photionisation processes and is of low or high opacity);
  2. Source the appropriate atomic data required;
  3. Be able to construct simple diagnostics, e.g. through the use of a simple three-level atomic model;
  4. To apply their knowledge to the solution of a practical astrophysical problem by either by direct analytical solution or by numerical modelling
Module Content:

Lectures + tutorials including problem sets for completion out of class covering aspects of spectroscopic diagnostic techniques applied to material ranging from the warm (≈104 K) and relatively dense gas in stellar atmospheres to the hot (≈106 – 107 K), dilute gas in stellar coronae.

Teaching and Learning Methods, including contact hours:

18 hours of lectures and tutorials.


An appreciation of spectra: emission and absorption, line and continuum. hours of lectures and tutorials.


A combination of continuous assessment and final examination.

Indicative Reading and Resources:

Mariska, J. T. "The Solar Transition Region", Cambridge University Press, 1992 Pradhan, A. and Nahar, S. "Atomic Astrophysics and Spectroscopy", Cambridge University Press, 2011

Other resources:

(Resource) NIST Atomic and Molecular Database, TopBase (atomic data) (Resource) CHIANTI – atomic data and optically thin solutions (high temperature plasmas)