Gama-ray emission from microquasars: leptonic vs hadronic models

G.E. ROMERO; V. BOSCH-RAMON; J. M. PAREDES; M. ORELLANA

Munich, Alemania

Conferencia; Relativistic astrophysics and cosmology -Einstein's legacy; 2005

MPA

Microquasars are X-ray binaries with non-thermal relativistic jets that are detected at radio wavelengths. In recent years there has been increasing evidence that the non-thermal emission could reach hard X-ray and gamma-ray energies. In this work we discuss two different types of models for the high-energy gamma-ray production in microquasars. On the one hand, we introduce a new leptonic model where the emission arises from inverse Compton interactions with both internal (synchrotron) and external photon fields, and  relativistic Bremsstrahlung from interactions with cold protons in the jet and the stellar wind material. The model takes consistently into account the accretion-jet ejection relationship, jet particle acceleration andpair creation effects on the observed spectrum. On the other hand, we introduce a hadronic model where the gamma-rays are the result of interactions between relativistic protons in the jet and cold protons from the anisotropic stellar wind. We consider the case of slow and dense equatorial stellar winds, as those presented by Be stars, with particular emphasis on the application to LSI +61 303. Spectral differences similarities between both types of models are briefly discussed