Measuring the polarization of prompt GRB emission with INTEGRAL: from astrophysics to fundamental physics

Author: Diego Götz

Abstract: The measure of polarization is an important and promising tool to investigate the geometry, the content, and the radiation processes at work in the relativistic flows, which originate the prompt emission of gamma-ray bursts.

IBIS on board INTEGRAL has moderate polarimetric capabilities, which lead to the measurement of linear polarization in the gamma-ray band (200-800 keV) for some bright sources, including Gamma-Ray Bursts.

To date polarization has been measured with IBIS for a handful of GRBs. Here I present the polarization results on two highly polarized GRBs, 041219A and 061122. These results, together with follow-up observations, used to identify the GRB host galaxies, allowed us to deeply constrain (Xi < 3.4e-16) the possibility of Lorentz Invariance Violation predicted by some quantum gravity theories through the vacuum birefringence effect.