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

TL;DR

This paper introduces the LAT Low-Energy (LLE) technique to analyze Fermi Gamma-Ray Bursts in the 30-100 MeV range, filling a gap between existing instruments and improving spectral analysis capabilities.

Contribution

The paper presents a novel LLE method that extends Fermi LAT analysis to lower energies, enabling better high-energy spectral constraints for GRBs.

Findings

LLE technique successfully recovers signals between 30 and 100 MeV.

Preliminary spectral analyses demonstrate the method's effectiveness.

Performance studies show promising results for future GRB analyses.

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.