High energy emission of symbiotic recurrent novae: RS Ophiuchi and V407   Cygni
  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. 
Margarita Hernanz (1) and Vincent Tatischeff (2) ((1) Institut de   Ciencies de l'Espai (CSIC-IEEC), (2) Centre de Spectrome...
astro-ph.HE