Observation of GRBs and TGFs with AGILE

Abstract

The AGILE satellite, in orbit since 2007, localized up to October 2009 about 1 Gamma Ray Burst (GRB) per month with the hard X-ray imager SuperAGILE (18 -60 keV) (with a rate reduced by a factor 2-3 in spinning mode) and is detecting around 1 GRB per week with the non-imaging Mini-Calorimeter (MCAL, 0.35 -100 MeV). Up to now the AGILE Gamma Ray Imaging Detector firmly detected four GRBs in the energy band between 20 MeV and few GeV. In this paper we review the status of the GRBs observation with AGILE and discuss the upper limits in the gamma-ray band of the non-detected events. Moreover AGILE is detecting hundreds of Terrestrial Gamma-ray Flashes (TGFs) with the MCAL instrument. Thanks to the MCAL energy range extended up to 100MeV and its flexible trigger logic on sub-millisecond time scales, AGILE is adding a wealth of observations which pose severe constrains on production models. In this presentation we will describe the characteristics of the AGILE TGF sample. Finally we present the first precise localization study of TGFs from space, carried out at gamma-ray energies above 20 MeV with the AGILE gamma-ray imager.