GRB Prompt Emission with Anisotropic Electron Distribution

Abstract The typical spectrum of the prompt emission gamma-ray bursts (GRBs) indicates that electron cooling is suppressed in spite strong magnetic field standard synchrotron model. Recent particle-in-cell simulations show particle acceleration by reconnection a magnetically dominated plasma can lead to small pitch angles especially low-energy region. Such angle prevents electrons from via radiation. In this paper, taking into account effects and adiabatic cooling, we numerically calculate spectra with anisotropic distributions. If require Poynting flux larger than 10 50 erg s −1 as model motivated reconnection, bulk Lorentz factor ∼1000 minimum γ min ∼ 4 are required reproduce GRB spectrum.