## The diffusion of radiation in moving media## II. Limits for large and small velocity gradients for deterministic lines
^{1} Institut für Theoretische Astrophysik, Tiergartenstrasse 15, 69121 Heidelberg, Germany^{2} Institut für Angewandte Mathematik, Im Neuenheimer Feld 294, 69120 Heidelberg, Germany^{3} Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Im Neuenheimer Feld 368, 69120 Heidelberg, Germany
The general formulae for radiative quantities in the diffusion
limit for a differentially moving 3D medium which have been derived in
Paper I of this series, are evaluated for the limiting cases of
very large and very small velocity gradients
. The extinction coefficient is
specified by the continuum and the contribution of spectral lines
which is formulated deterministically. For large
This article contains no SIMBAD objects. ## Contents- 1. Introduction
- 2. Basic expressions
- 3. Limit of large
*w* - 4. Limit of small
*w*- 4.1. Wavelength-integrated radiative quantities
- 4.2. Effects of various extinction distributions
- 4.2.1. Power-law continuum
- 4.2.2. Spectral edge
- 4.2.3. Single narrow line
- 4.2.4. Many spectral lines
- 5. The flux vector in moving 3D media
- 6. Conclusions and outlook
- Acknowledgements
- References
© European Southern Observatory (ESO) 2000 Online publication: July 7, 2000 |