The SNR W44: an ideal laboratory for Cosmic-Ray acceleration

W44 (G34.7-0.4) is one of the most studied Supernova Remnants (SNRs) because it is an ideal system to study Cosmic-Ray (CR) production, acceleration and propagation. In the last years, SNR study showed an increasingly complex scenario with a continuous rielaboration of theoretical models; moreover, until now, providing an experimental unambiguous proof of the CR origin has been elusive, despite many decades of attempts and controversial analysis. In this context the AGILE γ-ray satellite has an important role. During its five years of life it observed a great amount of different astrophysical sources, including SNRs. In case of W44 AGILE observed a spectrum extending to energies below E = 200 MeV that allows us to exclude leptonic emission as the main contribution to the γ-ray emission [36]. Moreover, refined AGILE data show that W44 spectrum could be the sum of two (or more) contributions from two different regions of the remnant where different processes influence CR acceleration and propagation. Future AGILE data will lead us to understand the intricate link between SNRs and CRs.