Spectropolarimetry of SN 1987A with the AAT

Spectropolarimetric observations of SN 1987A obtained with the Anglo-Australian Telescope are presented and discussed. The foreground interstellar polarization is estimated to have a value of 0.8% at position angle 40 deg. In the early stages polarization features on the absorption troughs of the P-Cygni profiles are observed. At later stages the polarization is dominated by the effects of electron scattering. After correction for the effects of interstellar polarization the position angle of the electron scattering polarization is 110 deg. The spectrum of the polarized radiation shows broad redshifted features corresponding to the emission lines which can be understood as the consequence of electron scattering in an expanding atmosphere. The position angle observed is consistent with the elongation of the supernova image seen by speckle interferometry. 14 refs., 8 figs., 1 tab