A Comprehensive Analysis of Fermi Gamma-Ray Burst Data. I. Spectral Components and Their Possible Physical Origins of LAT/GBM GRBs

Understand

We present a systematic analysis of the spectral and temporal properties of 17 GRBs co-detected by GBM and LAT on board the Fermi satellite by May 2010.

• We performed a time-resolved spectral analysis of all the bursts with the finest temporal resolution allowed by statistics, in order to avoid temporal smearing of different spectral components.
• We found that the time-resolved spectra of 14 out of 17 GRBs are best modeled with the Band function over the entire Fermi spectral range, which may suggest a common origin for emissions detected by LAT and GBM.
• GRB 090902B and GRB 090510 require the superposition between an MeV component and an extra power law component, with the former having a sharp cutoff above E_p.