Context. TeV gamma-ray emission from two massive binaries of the microquasar type, LS 5039 and LS I +61o 303, show clear variability with their orbital periods. Aims. Our purpose is to calculate the GeV and TeV γ-ray light curves from the massive binary LS 5039 which are expected in the specific Inverse Compton e pair cascade model. This model successfully predicted the basic features of the hi...

Context. Cygnus X-1 and LS 5039 are two X-ray binaries detected at TeV energies. Both sources are compact systems, contain jetlike (radio) structures, and harbor very luminous O stars. The two systems show TeV signal around the superior conjunction of the compact object, when the largest gamma-ray opacities are expected. Aims. We investigate the implications of the TeV detections of Cygnus X-1 ...

Context. Cygnus X-1 and LS 5039 are two X-ray binaries observed at TeV energies. Both sources are compact systems, contain jet-like (radio) structures, and harbor very luminous O stars. A TeV signal has been found around the superior conjunction of the compact object in both objects, when the highest gamma-ray opacities are expected. Aims. We investigate the implications of finding TeV emission...

We present new optical – near–IR spectroscopic and photometric observations of the newly discovered galactic microquasar LS 5039, which indicate a classification for the mass donor in the system of O6.5V((f)). Optical spectroscopy and photometry shows no variability over a timescale of years, and we find no evidence of modulation by, or emission from the compact companion in these data. However...

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Under the assumption that LS 5039 is a system composed by a pulsar rotating around an O6.5V star in a ∼ 3.9 day orbit, we present the results of a theoretical modeling of the high energy phenomenology observed by the High Energy Stereoscopy Array (H.E.S.S.). This model (including detailed account of the system geometry, Klein-Nishina inverse Compton, γ-γ absorption, and cascading) is able to de...

The microquasar LS 5039 has recently been detected as a source of very high energy (VHE) γ-rays. This detection, that confirms the previously proposed association of LS 5039 with the EGRET source 3EG J1824−1514, makes of LS 5039 a special system with observational data covering nearly all the electromagnetic spectrum. In order to reproduce the observed spectrum of LS 5039, from radio to VHE γ-r...

The microquasar LS 5039 has recently been detected as a source of very high energy (VHE) γ-rays. This detection, that confirms the previously proposed association of LS 5039 with the EGRET source 3EG J1824−1514, makes of LS 5039 a special system with observational data covering nearly all the electromagnetic spectrum. In order to reproduce the observed spectrum of LS 5039, from radio to VHE γ-r...

Microquasars are stellar x-ray binaries that behave as a scaled-down version of extragalactic quasars. The star LS 5039 is a new microquasar system with apparent persistent ejection of relativistic plasma at a 3-kiloparsec distance from the sun. It may also be associated with a gamma-ray source discovered by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the COMPTON-Gamma Ray Obs...