PHY232: The Dynamic Interstellar Medium

Crab nebula (courtesy VLT ESO) Horsehead nebula (courtesy VLT ESO) Orion nebula (courtesy VLT ESO) Dumbbell nebula (courtesy VLT ESO)


PHY232 is a second-semester course for second year undergraduates taking dual-honours Physics and Astrophysics students (discontinued since 2015/16). The images presented above illustrate various aspects of this course: From left to right: Supernova remnant ( Crab nebula), interstellar dust ( Horsehead nebula), a HII region ( Orion nebula cluster), a Planetary Nebula ( Dumbbell nebula).

Aims and Objectives

The interstellar medium comprises the gas and dust that is located between stars in galaxy. This module aims to present an overview of the various components of the ISM, and its relevance to the cosmic cycle and astronomical observations; develop students appreciation of how atomic physics impacts upon astrophysical applications, such as the determination of properties of an ionized plasma; familiarize students with spectroscopic analysis tools during laboratory sessions. An outline syllabus can be found here (pdf) while objectives are itemised here (pdf).

By the end of the module, students will be able to demonstrate a general knowledge of the principal constituents of the ISM; Show an understanding of the processes involved in the heating and cooling of interstellar gas; indicate a basic appreciation of the properties of dust grains, including their formation and destruction mechanisms; understand the basic properties of ionized regions for the pure hydrogen case and the more realistic situation involving trace metals; contrast photo-ionized with shock ionized nebulae, and understand the basics of gas dynamics for HII regions and supernova remnants; become familiar with manipulation of spectroscopic datasets through specialized software.


A laboratory exercise (script can be accessed here) involving spectroscopy contributes 20% of the module (deadline Tue 5 May 2015) -- download Figure 1, Figure 2, Figure 3, Figure 4, Figure 5). Video clips designed to complement the script are available from here. A final 2 hour exam contributes the remaining 80%.

Text Books

The Physics of the Interstellar Medium (2nd Ed), J Dyson & D Williams, 1997 (IoP) Essential

Physics of the interstellar and intergalactic medium, B.T. Draine (Princeton) Recommended

The Physics and Chemistry of the Interstellar Medium, A. Tielens, (CUP) Recommended

Astrophysics of Gaseous Nebulae & Active Galactic Nuclei, (2nd Ed.) D. Osterbrock & G Ferland, 2006 (University Science Books) Advanced

Lectures for (final) 2014/15 session

Lectures are held in LT-B on Tuesdays at 2pm and LT-4 on Fridays at 11am in the second semester.

Tue 10 Feb 15 - PHY232-1 Introduction; Historical context pdf

Fri 13 Feb 15 - PHY232-2 Molecular hydrogen pdf

Tue 17 Feb 15 - PHY232-3 Neutral gas pdf

Fri 20 Feb 15 - PHY232-4 Ionized hydrogen pdf

Tue 24 Feb 15 - PHY232-5 Hot gas; Cooling and heating pdf

Fri 27 Feb 15 - PHY232-6 Dust (part 1) pdf

Tue 3 Mar 15 - PHY232-7 Dust (part 2) pdf

Fri 6 Mar 15 - PHY232-8 Pure hydrogen nebulae pdf

Tue 10 Mar 15 - PHY232-9 Metals in nebulae pdf

Thu 12 Mar 15 (2pm, LT-C) - PHY232-10 Extinction, Ne, Te pdf

Tue 17 Mar 15 - PHY232-11 Lyman continuum, abundances pdf

Fri 20 Mar 15 - PHY232-12 Metallicity calibrations pdf

Tue 14 Apr 15 - No lecture (Beijing)

Fri 17 Apr 15 - no lecture (Beijing)

Thu 23 Apr 15 (2pm, F38) - Planetary Nebulae (notes in PHY232-12)

Fri 24 Apr 15 - PHY232-13 Nebulae in radio pdf

Tue 28 Apr 15 - PHY232-14 Gas dynamics pdf

Fri 1 May 15 - PHY232-15 Supernovae and supernova remnants pdf

Tue 5 May 15 - PHY232-16 Observations of star formation pdf

Fri 8 May 15 - PHY232-17 Theory of star formation pdf

Tue 12 May 15 - PHY232-18 Superwinds, starbursts pdf

Fri 15 May 15 - PHY232-19 Active Galactic Nuclei pdf

Mon 08 Jun 15 - Revision lecture (12:00-13:00, LT3)