Fermi Gamma-ray Space Telescope

GRB Spectral Analysis: A Cautionary Tale

J. Michael Burgess
Felix Ryde

Abstract:

Spectral analysis of GRBs in the Fermi era has opened new windows and raised new questions as we find that the empirical Band function is inadequate to describe a substantial fraction of the detected GRBs. The measurement of multiple components and spectral evolution provides an opportunity to cut away the forest of emission models. For example, the additional blackbody component observed in GRBs since the BATSE era has striking implications for understanding the structure of the outflow and source of the emission in the GRB jet. However, due to the complexity of these models, it is important to understand the systematics associated with these new analyses. Here, I present an analysis of our ability to measure spectral evolution and whether or not the blackbody component observed is an artifact of this spectral evolution. Additionally, I identify key factors to consider when using these new complex spectral analyses to make physical inferences.