Microquasar LS 5039: a TeV gamma-ray emitter and a potential TeV neutrino source

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Abstract
The recent detection of TeV -rays from the microquasar LS 5039 by HESS is one of the most exciting discoveries of observational gamma-ray astronomy in the very high energy regime. This result clearly demonstrates that X-ray binaries with relativistic jets (microquasars) are sites of effective acceleration of particles (electrons and/or protons) to multi-TeV energies. Whether the -rays are of hadronic or leptonic origin is a key issue related to the origin of Galactic Cosmic Rays. We discuss different possible scenarios for the production of -rays, and argue in favor of hadronic origin of TeV photons, especially if they are produced within the binary system. If so, the detected -rays should be accompanied by a flux of high energy neutrinos emerging from the decays of �± mesons produced at pp and/or p interactions. The flux of TeV neutrinos, which can be estimated on the basis of the detected TeV -ray flux, taking into account the internal ! e+e absorption, depends significantly on the location of -ray production region(s). The minimum neutrino flux above 1 TeV is expected to be at the level of 10 12 cm 2s 1; however, it could be up to a factor of 100 larger. The detectability of the signal of multi-TeV neutrinos significantly depends on the high energy cutoff in the spectrum of parent protons; if the spectrum of accelerated protons continues to 1 PeV and beyond, the predicted neutrino fluxes can be probed by the planned km3-scale neutrino detector.