Published in Space Science Reviews, Volume 134, Issue
1-4, pp. 155-190, 2008.
astro-ph/0801.1011
For a PDF version of the article, click here.
THERMAL RADIATION PROCESSES
J.S. Kaastra1,
F.B.S. Paerels2,
F. Durret3,
S. Schindler4
and P. Richter5
1 SRON
Netherlands Institute for Space Research, Sorbonnelaan 2,
3584 CA Utrecht, Netherlands
Astronomical
Institute,
Utrecht
University P.O. Box 80000, 3508 TA Utrecht, The Netherlands
J.Kaastra@sron.nl
2
Department of
Astronomy,
Columbia
University, New York, NY, USA
3 Institut
d'Astrophysique de Paris, CNRS, UMR 7095, Université Pierre et
Marie Curie, 98bis Bd Arago, F-75014 Paris, France
4 Institute for Astro- and Particle Physics,
University of
Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
5 Physics Institute,
Potsdam
University, Am Neuen Palais 10, D-14469 Potsdam, Germany
Abstract. We discuss the different physical processes that are
important to understand the thermal X-ray emission and absorption
spectra of the diffuse gas in clusters of galaxies and the warm-hot
intergalactic medium. The ionisation balance, line and continuum
emission and absorption properties are reviewed and several practical
examples are given that illustrate the most important diagnostic
features in the X-ray spectra.
Key words: atomic processes - radiation mechanisms: thermal -
intergalactic medium - X-rays:general
Table of Contents
INTRODUCTION
- A SHORT INTRODUCTION TO ATOMIC STRUCTURE
- The Bohr atom
- Level notation in multi-electron systems
- Binding energies
- Abundances
- BASIC PROCESSES
- Excitation processes
- Ionisation processes
- Recombination processes
- Charge transfer processes
- IONISATION BALANCE
- Collisional Ionisation Equilibrium (CIE)
- Non-Equilibrium Ionisation (NEI)
- Photoionisation Equilibrium (PIE)
- EMISSION PROCESSES
- Continuum emission processes
- Line emission processes
- Some important line transitions
- ABSORPTION PROCESSES
- Continuum versus line absorption
- Continuum absorption
- Line absorption
- Some important X-ray absorption lines
- Curve of growth
- Galactic foreground absorption
- GALACTIC FOREGROUND EMISSION
- COOLING FUNCTION
- IONISATION AND EXCITATION BY NON-THERMAL
ELECTRONS
- PLASMA MODELLING
- Available codes
- Important parameters
- Multi-Temperature emission and absorption
- REFERENCES
