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The 2009 Fermi Symposium

The Epeak-Fluence Bimodality: A Fundamental Discriminator Between Long and Short GRBs

Adam Goldstein, UA Huntsville


Using the derived Epeaks and fluences from the complete and final BATSE 5B Spectral Catalog (Goldstein & Mallozzi, in prep), we study the bulk characteristics of the Epeak-fluence relation for GRBs. The relation appears to be a fundamental discriminator between long and short bursts, as well as representing an intrinsic hardness ratio for GRBs. We discuss the results of the lower limit test of the Epeak-Eiso relations in the Epeak-fluence plane for BATSE bursts with no observed redshift. Implications for short GRB progenitors will be discussed, as well as the implications for future detections by Fermi. In addition, a preliminary investigation of the Epeak-Eiso relations for Fermi/GBM bursts with redshift will be presented. These bursts directly provide a first look at how the relations hold up over a larger energy band than previously had been explored.