Andrea Giuliani

MAX: a gamma-ray lens for nuclear astrophysics

The mission concept MAX is a space borne crystal diffraction telescope, featuring a broad-band Laue lens optimized for the observation of compact sources in two wide energy bands of high astrophysical relevance. For the first time in this domain, gamma-rays will be focused from the large collecting area of a crystal diffraction lens onto a very small detector volume. As a consequence, the background noise is extremely low, making possible unprecedented sensitivities. The primary scientific objective of MAX is the study of type Ia supernovae by measuring intensities, shifts and shapes of their nuclear gamma-ray lines. When finally understood and calibrated, these profoundly radioactive events will be crucial in measuring the size, shape, and age of the Universe. Observing the radioactivities from a substantial sample of supernovae and novae will significantly improve our understanding of explosive nucleosynthesis. Moreover, the sensitive gamma-ray line spectroscopy performed with MAX is expected to clarify the nature of galactic microquasars (e+e- annihilation radiation from the jets), neutrons stars and pulsars, X-ray Binaries, AGN, solar flares and, last but not least, gamma-ray afterglow from gamma-burst counterparts.

Gamma-Light: High-Energy Astrophysics above 10 MeV

The energy range between 10 and 50 MeV is an experimentally very difficult range and remained uncovered since the time of COMPTEL. Here we propose a possible mission to cover this energy range.

Gamma-ray imaging by silicon detectors in space: Presentation of the AGILE reconstruction method and kalman filter algorithms

We present the AGILE REconstruction Method (AREM) and the track finding optimization by Kalman filter algorithms. AREM is a method of γ-ray direction reconstruction to be applied to high-resolution Silicon Tracker detectors in space. It can be used in a “fast mode,” independently on Kalman filters techniques, or in an “optimized mode,” including Kalman filter algorithms for track identification. AREM correctly addresses three points of the analysis which become relevant for off-axis incidence angles: 1) intrinsic ambiguity in the identification of the 3-De+/e− tracks and conversion plane; 2) proper identification of the 3-D reconstructed direction; 3) careful choice of an energy weighting scheme for the 3-D tracks. We present the preliminary results of the angular resolution obtained by analyzing simulated γ-rays in the AGILE detector. The excellent spatial resolution obtained by the AGILE Silicon Tracker allows to improve the angular resolution by a factor ∼2 at energies ≳ 400 MeV with respect to previou...