Fermi/GBM and BATSE Gamma-Ray Bursts: comparison of the spectral properties

Understand

The Gamma-ray Burst Monitor (GBM) on board Fermi allows to study the spectra of Gamma Ray Bursts (GRBs) over an unprecedented wide energy range (8 keV - 35 MeV).

• We compare the spectral properties of short and long GRBs detected by the GBM (up to March 2010) with those of GRBs detected by the BATSE instrument on board the CGRO.
• GBM and BATSE long bursts have similar distributions of fluence (F), Epeak and peak flux (P) but GBM bursts have a slightly harder low-energy spectral index \alpha with respect to BATSE GRBs.
• GBM and BATSE short bursts have similar distributions of fluence, \alpha and peak flux, with GBM bursts having slightly larger Epeak.