Detection of Terrestrial Gamma-Ray Flashes up to 40 MeV by the AGILE satellite
Marisaldi, M ; Fuschino, F ; Labanti, C ; P. Giommi, and L. Salotti
Jan - 2009


Volume : 115 ; Issue : A00E13
type: Article Journal

We report the detection by the Astrorivelatore Gamma a Immagini Leggero (AGILE)satellite of terrestrial gamma ray flashes (TGFs) obtained with the minicalorimeter(MCAL) detector operating in the energy range 0.3–100 MeV. We select events typicallylasting a few milliseconds with spectral and directional selections consistent with theTGF characteristics previously reported by other space missions. During the period 1 June2008 to 31 March 2009 we detect 34 high‐confidence events showing milliseconddurations and a geographical distribution peaked over continental Africa and SoutheastAsia. For the first time, AGILE‐MCAL detects photons associated with TGF events up to40 MeV. We determine the cumulative spectral properties of the spectrum in the range0.5–40 MeV, which can be effectively described by a Bremsstrahlung spectrum. We findthat both the TGF cumulative spectral properties and their geographical distribution are ingood agreement with the Reuven Ramaty High Energy Solar Spectroscopic Imager(RHESSI) results.

keywords :