Inverse Compton e± pair cascade model for the γ-ray production in massive binary LSI+61° 303

We apply an inverse Compton e(+/-) pair cascade model for gamma-ray production in the massive binary system LSI +61 degrees 303 assuming that electrons are accelerated already inside the inner part of the jet launched by the compact object. gamma-ray spectra, affected by the cascade process, and lower energy spectra, from the synchrotron cooling of the highest energy electrons in the jet, are calculated as a function of the phase of this binary system. gamma-ray spectra expected in such a model have different shape than those ones produced by electrons in the jet directly to observer. Moreover, the model predicts clear anticorrelation between gamma-ray fluxes in the GeV (1-10 GeV) and TeV (>200 GeV) energy ranges with the peak of the TeV emission at the phase similar to 0.5 (the peak half-width ranges between the phases similar to 0.4-0.9, for the inclination of the binary system equal to 60 degrees, and similar to 0.4-0.1 for 30 degrees). The fine features of TeV gamma-ray emission (fluxes and spectral shapes) as a function of the phase of the binary system are consistent with recent observations reported by the MAGIC collaboration. Future simultaneous observations in the GeV energies (by the GLAST and AGILE telescopes) and in the TeV energies (by the MAGIC and VERITAS telescopes) should test other predictions of the considered model supporting or disproving the hypothesis of acceleration of electrons already in the inner part of the microquasar jets.