The LAT Low-Energy technique for Fermi Gamma-Ray Bursts spectral analysis

Abstract

Fermi Large Area Telescope (LAT) data analyses based on event reconstruction and classification are so far restricted to events of measured energy larger than 100 MeV. We present a new technique to recover the signal from Gamma-Ray Bursts' (GRB) prompt emission between ~30 MeV and 100 MeV, which differs from the standard LAT analysis. Filling the gap between the energy ranges where the Gamma-ray Burst Monitor (GBM) and LAT operate is important to better constrain the high-energy spectra of GRBs. The LAT Low-Energy (LLE) technique is described, first performance studies are presented, as well as preliminary spectral re-analyses of two Fermi GRBs.