High-energy astrophysics research is based on two complementary methodologies. Satellite observations, such as those performed by the AGILE and the large area telescope on board the Fermi space mission, cover the energy band from scores of MeV up to hundreds of GeV. Observations in this band are related mainly to compact objects like neutron stars and galactic or extra-galactic black holes. Observations of the galaxy in gamma rays enables us to obtain interesting information regarding matter and interstellar radiation thanks to interactions between cosmic rays.
At higher energies, the technique consists of observing from the earth the electromagnetic showers produced by photons in the upper atmosphere. The scientific goals of the two methods are therefore complementary.
(Text downloaded from df.units.it)