Wiley, Monthly Notice- Royal Astronomical Society -Letters-, 1(433), p. L20-L24
Full text: Download
Spectropolarimetry provides the means to probe the 3D geometries of Supernovae at early times. We report spectropolarimetric observations of the Type Ia Supernova 2012fr at four epochs: -11, -5, +2 and +24 days, with respect to B-lightcurve maximum. SN 2012fr is a normal Type Ia SN, similar to SNe 1990N, 2000cx and 2005hj (that all exhibit low velocity decline rates for the principal Si II line). The SN displays high velocity components at -11 days that are highly polarized. The polarization of these features decreases as they become weaker from -5 days. At +2 days, the polarization angles of the low velocity components of silicon and calcium are identical and oriented at 90 degrees relative to the high velocity Ca component. In addition to having very different velocities, the high and low velocity Ca components have orthogonal distributions in the plane of the sky. The continuum polarization for the SN at all four epochs is low