Spectropolarimetric Signatures of Clumpy Supernova Ejecta

Type Conference Paper
Names K. Tabetha Hole, D. Kasen, K. Nordsieck
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #215, #333.05
Volume 42
Pages 432
Date January 1, 2010
URL http://adsabs.harvard.edu/abs/2010AAS...21533305T
Library Catalog NASA ADS
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 and size of clumps (and the related effect of covering fraction) 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, can constrain the 3-D structure of supernova ejecta and offer important insight into the SN explosion physics and the nature of their progenitor system. This research was funded in part by the National Science Foundation through grant AST-0807664.
UW-Madison Astronomy Home