  Recurrent novae occurring in symbiotic binaries are candidate sources of high
energy photons, reaching GeV energies. Such emission is a consequence of
particle acceleration leading to pion production. The shock between matter
ejected by the white dwarf, undergoing a nova explosion, and the wind from the
red giant companion is responsible for such a process, which mimics a supernova
remnant but with much smaller energetic output and much shorter time scales.
Inverse Compton can also be responsible for high energy emission. Recent
examples are V407 Cyg, detected by Fermi, and RS Oph, which unfortunately
exploded in 2006, before Fermi was launched.
