Investigating Polarization Signatures from GRB Models

Abstract There is still much debate around the inner workings of the gamma-ray-burst (GRB) prompt emission phase, with many questions still left unanswered. Polarization signatures offer a promising new avenue for discriminating between the various GRB prompt emission models. The aim of this study is to estimate the energy- and time-resolved polarization signatures resulting from inverse Compton (IC) scattering for two specific GRB prompt emission models—namely, the backscattering-dominated cork model of M. K. Vyas et al. and a Compton drag model of G. Ghisellini et al. In order to achieve this, we apply an IC polarization Monte Carlo algorithm to those two GRB models, in order to estimate the expected polarization signatures. For the backscattering-dominated cork model, we find polarization signatures below ∼10%, likely below the detection limits of current or near-future X-ray and gamma-ray polarimeters. Our results for the Compton drag model indicate polarization results consistent with those found by D. Lazzati et al. Furthermore, we find some energy and time dependence of the estimated polarization, particularly for the polarization angle.