2012 Volume 67 Issue 11 Pages 758-762
Polarization of Gamma-ray bursts (GRBs) is detected with GAP onboard IKAROS. Within the standard fireball framework, prompt emission of GRBs is understood as the result of synchrotron radiation of the internal shocks. If this is true, the radiation could be highly polarized. We confirmed the high polarization degree of GRB 100826A. The origin of magnetic fields is interesting.