The ASTROGAM Concept

ASTROGAM is a concept for a breakthrough observatory space mission, with a detector composed of a silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the nonthermal Universe in the photon energy range from fractions of an MeV to a few GeV. The instrument measures simultaneously the energy and direction of gamma rays by combining a Compton and a pair-production detector. It consists of a telescope made of tens of planes of silicon, a calorimeter made of scintillation detectors, and an anticoincidence detector to veto the background. All of the required detector technology is nowadays well proven. Thanks to its performance in the largely unknown MeV-GeV domain, ASTROGAM can open a new window on the nonthermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on their surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, ASTROGAM can determine the origin of key isotopes fundamental for our understanding of supernova explosions and the chemical evolution of our Galaxy. The mission can provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories operating at different wavelengths and in a multimessenger context, as well as to the particle physics community.