Fermi Gamma-ray Space Telescope

Fitting a subphotospheric dissipation model to Fermi gamma-ray burst data

Ahlgren
Josefin Larsson, Tanja Nymark, Asaf Pe'er, Felix Ryde

Abstract:

The prompt emission mechanism of gamma-ray-bursts (GRBs) is still unknown. While GRB spectra are usually well fitted with the Band function, this gives little understanding of the underlying radiation mechanism. In this work we fit a sample of bright Fermi bursts with a physical model (Pe'er et al. 2005). The model simulates subphotospheric dissipation in a relativistically expanding fireball and includes emission from Compton and Inverse Compton scattering, synchrotron as well as pair production/annihilation . We show that this model provides good fits to the data and discuss the physical implications of the best-fit parameters.