Polarimetry of the Type Ia Supernova SN 1996X

摘要

We present broadband and spectropolarimetry of the Type Ia SN 1996X obtained on 1996 April 14 (UT), and broadband polarimetry of SN 1996X on 1996 May 22 (UT), i.e., about 1 week before and 4 weeks after optical maximum, respectively. The Stokes parameters derived from the broadband polarimetry are consistent with zero polarization. The spectropolarimetry, however, shows broad spectral features that are due intrinsically to an asymmetric supernova atmosphere. The degree of this intrinsic component is low (～0.3/100). Unlike polarization in Type II SN, the features of SN 1996X are much more richly structured and show no strong correlation with the features in the flux. Model calculations show that the polarization is produced by Thomson scattering but the spectral features are governed by line blending.