(contact: Re'em)
Title:
Thermal and non-thermal emission during the prompt phase of GRBs
Abstract:
The launch of Fermi opened a new era in the study of Gamma-Ray Bursts
(GRBs) prompt emission. The broad band data show complex behavior
that urge the need for a new interpretation. I will show that
photospheric (thermal) emission is naturally expected. Light
aberration in this relativistically expanding environment modifies the
Planck spectrum that is expected to be observed as a multicolor
black-body emission component. Moreover, these photons serve as seed
photons for Compton scattering by energetic electrons, following
kinetic energy dissipation above the photosphere. The high energy
spectrum therefore results from various radiative processes, and as
such is not easy to model. I will show how the analysis method
proposed results in a complete, self consistent picture of the
physical conditions at both emission sites of the thermal and
non-thermal radiation. Furthermore, it enables a new insight into the
physical conditions in the innermost regions of the outflow, hence
constrain progenitor models.
References
Pe'er & Ryde, 2010, arXiv:1008:4590
Pe'er et. al., 2010, arXiv:1007:2228
Ryde et al., 2010, ApJ, 709, L172
Ryde & Pe'er, 2009, ApJ, 702, 1211
Pe'er, 2008, ApJ, 682, 436