Predicting spectral parameters in the backscattering dominated model for the prompt phase of GRBs

Abstract

We present new results of the backscattering dominated prompt emission model in which the photons generated through pair annihilation at the centre of a gamma ray burst (GRB) are backscattered through Compton scattering by an outflowing stellar cork. %We show that the produced spectral features are capable of producing spectral features that are widely observed in GRBs. Using Comptonized pair annihilation spectrum accompanied by bremsstrahlung radiation for seed photons, we show that the obtained spectra produce low energy photon index in the range $\alpha \sim -1.95$ to $-1.1$, steeper high energy slopes $\beta \sim -3.5$ to $-2.4$ and spectral peak energies $\sim$ few KeV to few $10\times$ MeV. These findings are consistent with the values covered in GRB prompt phase observations.