A Time Dependent Numerical Leptonic Model for γ-ray Emitting Microquasars - Application to LS 5039

HESS has recently detected Very High Energy (VHE) γ-ray emission and its orbital modulation for the high mass X-ray binary and microquasar candidate LS 5039. Part, but not all of this orbital modulation can be attributed to the γγ absorption of the VHE γ-rays in the intense photon field of the stellar companion. We have applied a time-dependent leptonic model incorporating a full KleinNishina treatment of the Compton scattering as well as the angle dependence of the stellar radiation field to the broadband spectral energy distribution of LS 5039. We suggest that a modulation in the injection spectral index and the electron injection luminosity in addition to the γγ absorption might be a possible cause for the observed orbital modulation of the TeV flux and spectral shape. We do a detailed parameter study of various physical properties of the system to see their signature on the X-ray Hardness Intensity Diagrams (HID)s and light curves, predicting spectral hysteresis features, giving us an insight into the individual emission mechanisms in X-rays energies. Subject headings: radiation mechanisms: non-thermal — gamma-rays: theory — X-rays: binaries