Compton drag as a mechanism for very high linear polarization in Gamma-Ray Bursts

The recent discovery of a very high degree of linear polarization in the prompt emission of GRB 021206 (Coburn & Boggs 2003) has suggested that synchrotron emission may play a dominant role in the production of the prompt γ-ray photons. We here show that, under certain geometrical conditions, an even higher level of linear polarization is expected if the photons are produced by bulk inverse Compton scattering. We discuss the probability of realizing such geometrical conditions showing that, for a particularly bright burst as GRB 021206, the detection of polarization at the first attempt in the Compton drag scenario is not unlikely.