Stokes Parameter Analysis of XL-Calibur Data

XL-Calibur is a second-generation, balloon-borne hard X-ray scattering polarimeter in the 15–80 keV energy range. Data from XL-Calibur will constrain the geometry of the accretion column in accreting pulsars, the corona geometry in accreting stellar-mass black holes, and the hard X-ray emission region in the Crab pulsar. Stokes parameters allow a precise statistical analysis of X-ray polarization data, and they enable a simple but powerful forward-folding fit of spectropolarimetric models to the data. This chapter describes the foundations of these methods and their application to XL-Calibur data.