Analysis of transient spectra in scattering-dominated plasmas

Author: Atul Chhotray

Abstract: We perform Monte Carlo simulations of (inverse) Compton scattering in photon-lepton plasmas in non-equilibrium conditions relevant to dissipative GRB photospheres. These simulations allow us to study the transient behavior of the emergent photon spectra as the system evolves towards equilibrium after it has been affected by a sudden electron acceleration, such as in a collisionless shock or magnetic reconnection event. We explore different values of the lepton to photon ratio and of the radiation and particle temperatures, allowing for the injection of non-thermal leptons. We show that transient non-thermal spectra can be observed even in the absence of non-thermal phenomena during the equilibration time and we compare the spectra and spectral evolution of our synthetic spectra to GRB observations.