Hadronic gamma-ray production in microquasars with equatorial winds

ORELLANA, M.; ROMERO, G. E

Pucon, Chile

Congreso; XI IAU Regional Latin American Meeting of Astronomy; 2005

IAU

Microquasars are accreting X-ray binary systems with non-thermal radio jets. When the primary is a high-mass early-type star, the compact object accretes from the stellar wind. In some cases, like LS I + 61 303, the wind forms an equatorial disk and the secondary moves through it. In such a situation a strong interaction between the relativistic flow and the dense wind material is unavoidable and could result in the generation of high-energy emission. This is particularly interesting since microquasars have been recently confirmed to be high-energy ã-ray sources. We present here a hadronic model for gamma-ray production in this kind of systems, with a specific application to the case of LS I + 61 303. We calculate the gamma-ray emission originated in pp interactions between relativistic protons in the jet and cold protons from the wind. The emission from secondary electron-positron pairs is estimated as well. After taking into account opacity effects on the gamma-rays introduced by the different photons fields, we present high-energy spectral predictions that can be tested with the new generation Cherenkov telescopes like MAGIC and HESS.