The γ-ray sources in classical novae

The interaction between novae ejecta and accretion disks or circumbinary ( CB) disks surrounding nova systems based on the diffusive shock acceleration ( DSA) mechanism are investigated. Results suggest that interaction between the novae ejecta and CB disks most probably produce gamma-rays. Both leptonic and hadronic scenarios can feasibly produce gamma-rays in CB disks. A grid is calculated in order to discuss the gamma-ray sources in classical novae ( CNe), and results indicated that the mass of a white dwarf and the orbit period in CNe can greatly affect the production of gamma-rays. According to the proposed grid and synthesis population method, it is estimated that the percentage of CNe that can produce gamma-rays ranges from approximately 0.17 % to 51 % for leptonic scenarios when the magnetic field strength in the shock region ranges from 0.005 G to 0.02 G. The occurrence rate of gamma-ray CNe ranges from approximately 1 yr(-1) to 27 yr(-1) in the galaxy. The corresponding percentage ranges from approximately 64 % to 97 % in hadronic scenarios, while the occurrence rate of gamma-ray CNe ranges from approximately 35 yr(-1) to 52 yr(-1) in the galaxy.