Talk detail

Participant	Guiriec, Sylvain
Institution	NASA Goddard Space Flight Center - 3132, 16th Street NW - Washington - DC - USA

Session	GRB1	Accepted		Order	Time
Talk	Oral abstract	Title	Multi-Component Spectral Analysis of Fermi GRBs: a Step Forward in the Understanding of the Prompt Emission
Co-authors
Abstract	Observations of Gamma-Ray Bursts (GRBs) with the Fermi Gamma Ray Space Telescope, open a new window in the understanding of their prompt emission. With data sets from instruments prior to Fermi, GRB prompt emission spectra in the keV-MeV energy range were adequately fit with the empirical Band function, which consists of two power laws (PLs) smoothly connected at a break energy. Spectral analysis over the broad energy range of Fermi breaks this paradigm and reveals that GRB spectra are sometimes best fit with a combination of multiple components such as a Band function and a PL, a Band function and a thermal component or a Band function, a PL and a thermal component. While the parameters of the empirical Band function often challenge the physical models in the Band-only scenario, they can be more easily reconciled with synchrotron emission in the multi-component scenarios. A new Era is now open, unveiling the physical processes and the dissipation mechanisms producing the prompt emission as well as the nature of the energy reservoirs powering GRB jets.