A 3D radiative transfer framework
VII. Arbitrary velocity fields in the Eulerian frame
Hamburger Sternwarte, Gojenbergsweg 112
e-mail: firstname.lastname@example.org; email@example.com
2 Dept. of Physics and Astronomy, University of Oklahoma, 440 W. Brooks, Rm 100, Norman, OK 73019, USA
3 Computational Research Division, Lawrence Berkeley National Laboratory, MS 50F-1650, 1 Cyclotron Road, CA 94720-8139, USA
Accepted: 17 July 2010
Aims. A solution of the radiative-transfer problem in 3D with arbitrary velocity fields in the Eulerian frame is presented. The method is implemented in our 3D radiative transfer framework and used in the PHOENIX/3D code. It is tested by comparison to our well-tested 1D co-moving frame radiative transfer code, where the treatment of a monotonic velocity field is implemented in the Lagrangian frame. The Eulerian formulation does not need much additional memory and is useable on state-of-the-art computers, even large-scale applications with 1000’s of wavelength points are feasible.
Methods. In the Eulerian formulation of the problem, the photon is seen by the atom at a Doppler-shifted wavelength depending on its propagation direction, which leads to a Doppler-shifted absorption and emission. This leads to a different source function and a different Λ∗ operator in the radiative transfer equations compared to the static case.
Results. The results of the Eulerian 3D spherical calculations are compared to our well-tested 1D Lagrangian spherical calculations, the agreement is, up to vmax = 1 × 103 km s-1 very good. Test calculation in other geometries are also shown.
Key words: radiative transfer
© ESO, 2010