On March 2010, the symbiotic binary V407 Cyg erupted as a result of a nova explosion. The event gave rise to a two-week long burst of >100MeV gamma-rays detected by Fermi LAT, a unique observation testifying to particle acceleration in the system. The outburst can be considered a scaled-down supernova, with short dynamical time scale, and thus can constitute a test case for theories of the origin of galactic cosmic rays. We developed a model for diffusive shock acceleration and non-thermal emission in V407 Cyg, complemented by an evaluation of the thermal emission from the shocked plasma. We considered both leptonic and hadronic contributions to the non-thermal processes, and investigated the effect of many binary and nova parameters.
From the comparison to gamma-ray, X-ray and radio data, we obtain estimates for the maximum particle energies, the non-thermal energy budget, the relative contribution of electrons and protons to the emission, and the geometry of the binary system. We consider another similar event, the 2006 outburst of RS Oph, and then evaluate the contribution of novae in symbiotic systems to the Galactic cosmic rays, and the prospects for future detections of such objects in high-energy gamma-rays. Last, we discuss the possible origin of gamma-ray emission from classical novae and in particular the recently detected Nova Sco 2012.