| Abstract |
Polarization has been detected at early times for all types of
supernova, indicating that all such systems result from or quickly
develop some form of asymmetry. In addition, the detection of strong
line polarization in supernovae is suggestive of chemical
inhomogeneities ("clumps") in the layers above the photosphere, which
may reflect hydrodynamical instabilities during the explosion. We have
developed a fast, flexible, approximate semi-analytic code for modeling
polarized line radiative transfer within 3-D inhomogeneous
rapidly-expanding atmospheres. Given a range of model parameters, the
code randomly generates sets of clumps in the expanding ejecta and
calculates the emergent line profile and Stokes parameters for each
configuration. The ensemble of these configurations represents both the
effects of various host geometries and of different viewing angles. We
present results for the first part of our survey of model geometries,
specifically the effects of the number of clumps, size and distance from
the photosphere (and the related effect of filling factor) on the
emergent spectrum and Stokes parameters. We have also developed a method
to connect the results of our simulations to robust observational
parameters such as maximum degree of polarization and polarized flux
throughout the line. Our models, in connection with spectropolarimetric
observations, will be useful in constraining the 3-D structure of
supernova ejecta, which may offer important insight into the supernova
explosion physics or the nature of the progenitor system. |