Potential Gamma-ray Emissions from Low-Mass X-ray Binary Jets

By proposing a pure leptonic radiation model, we study the potential gamma-ray emissions from jets of the low-mass X-ray binaries. In this model, the relativistic electrons that are accelerated in the jets are responsible for radiative outputs. Nevertheless, dynamics of jets are dominated by the magnetic and proton-matter kinetic energies. The model involves all kinds of related radiative processes and considers the evolution of relativistic electrons along the jet by numerically solving the kinetic equation. Numerical results show that the spectral energy distributions can extend up to TeV bands, in which synchrotron radiation and synchrotron self-Compton scattering are dominant components. As an example, we apply the model to the low-mass X-ray binary GX 339-4. The results can not only reproduce the currently available observations from GX 339-4, but also predict detectable radiation at GeV and TeV bands by Fermi and CTA telescopes. The future observations with Fermi and CTA can be used to test our model, which could be employed to distinguish the origin of X-ray emissions.
Comment: 10 pages, 6 figures, accepted for publication in ApJ