SIMBAD references

Hjorth et al. (1999Sci...283.2073H) reported an upper limit on the linear polarization of the optical afterglow for GRB 990123 (P<2.3%). One of the interpretations for this small value of P was that the emission was probably due a relativistic jet with ordered magnetic field, and the viewing angle in the lab frame θ'≲Γ^–1, where Γ is the bulk Lorentz factor of the jet. We point out that this conclusion is incorrect and resulted from a confusion between the angles measured in the lab frame (θ') and in the plasma rest frame (θ).