Talk detail

Participant	McGlynn, Sinead
Institution	Excellence Cluster Universe - Boltzmannstrasse 2 - Garching - Bavaria - Germany

Session	GRB1	Accepted		Order	Time
Talk	Oral abstract	Title	Photospheric Emission in Fermi Gamma Ray Burst Monitor GRBs
Co-authors
Abstract	The Fermi satellite has been in orbit for four years, and its unprecedented energy range has led to the discovery of several new phenomena in gamma ray burst prompt spectra. This includes several cases where photospheric emission is present in the spectra. We discuss the systematic time-resolved analysis of the brightest gamma-ray bursts observed by the Gamma ray Burst Monitor (GBM) on Fermi up to the end of 2011, where the prompt spectra show evidence for photospheric emission. We use the observed spectral parameters to determine the dynamics of the outflow in each burst. This extensive sample illustrates that photospheric emission may be present to a greater or lesser degree in each burst, depending on the level of subphotospheric dissipation present.

Session	GRB3	Accepted		Order	Time
Talk	Oral abstract	Title	GeV Emission in Fermi GRBs
Co-authors
Abstract	The Fermi Gamma-ray Space Telescope has been in orbit for four years. Fermi has observed over 800 GRBs in this period, 36 of which have significant emission at high energies as observed by the Large Area Telescope (LAT) onboard. Here we present highlights of these observations, including the multi-component nature of the prompt spectra, the highest photon energies observed in GRBs to date, and the observed delay between keV and GeV emission. We discuss the theoretical implications and possible emission mechanisms responsible for these phenomena.