Introduction to Supernova Polarimetry

Abstract

The main purpose of this chapter is to help the reader understand an observational paper on supernova polarimetry, write an observing proposal, and plan photo- metric observations and reduce the resulting data. Although it focuses on the specific case of supernovae, the concepts presented here are applicable to other astrophysical cases. After introducing the mathematical formalism in the context of classical wave theory, the chapter follows with a description of the Stokes parameters and their physical meaning. It then presents the basics of dichroism, phase retardation, and birefringence to provide the required framework for understanding the workings of astronomical polarimeters. The discussion mainly deals with linear polarimetry, but circular polarimetry is also briefly treated. After illustrating the main instrumental problems, the chapter goes through the basic steps of data reductions and error estimates. The rest of the chapter is dedicated to a summary of the findings in the supernova field, by going through the polarimetric properties of the main sub-types.