Polarization Profiles of Scattered Emission Lines. III.
Effects of Multiple Scattering and Non-Rayleigh Phase Functions
W. J. Henney, IA-UNAM, Mexico
D. J. Axon, STScI, USA
Astrophysical Journal, 454, 233-253 (November 20 1995)
Abstract:
The techniques of
Henney (1994) for interpreting
spectropolarimetric observations of emission line scattering are
extended to cover moderately optically thick cases and cases in
which the scatterers are dust particles with a size that is not
negligible compared with the wavelength of the scattered light.
Particular attention is paid to the problem of the scattering of the
emission lines from a light source moving within a cloud of dust. It
is found that in many cases it is possible to infer the
three-dimensional relative velocity vector between the emitting
source and the scattering cloud from observations of the scattered
spectra from two different areas of the cloud. This method of
spectropolarimetric tomography is largely insensitive to the
scattering phase function of the dust and to the optical depth of
the cloud, showing that approaches based on the single scattering
assumption have a surprisingly broad range of validity.
Available as.............
Will Henney