Compton Electrons and Electromagnetic Pulse in Supernovae and Gamma-Ray Bursts

When gamma-rays emerge from a central source they may undergo Compton scattering in surrounding matter. The resulting Compton-scattered electrons radiate. Coherent radiation by such Compton electrons follows nuclear explosions above the Earth's atmosphere. Particle acceleration in instabilities produced by Compton electron currents may explain the radio emission by SN1998bw. Bounds on coherent radiation are suggested for supernovae and gamma-ray bursts; these bounds are very high, but it is unknown if coherent radiation occurs in these objects.