Julian Sitarek, Włodzimierz Bednarek
Microquasars have been expected to emit high energy gamma-rays due to their
general similarities to the gamma-ray emitting blazars (evidences of
relativistic jets, non-thermal radio to X-ray emission). In fact, the first
source of this type, Cyg X-3, has been recently unambiguously discovered by the
satellite telescopes. We study the features of the gamma-ray radiation produced
in these sources by relativistic electrons, accelerated in the inner part of
the jet. The electrons initiate an Inverse Compton e^\pm pair cascade in the
radiation field of the accretion disk. Due to the anisotropy of the accretion
disk radiation field, the spectra of gamma-rays show strong dependence on the
observation angle, the location of the emission region within the jet and the
details of the acceleration process. As an example, we confront our model with
the observations of the microquasar Cyg X-3, which has been recently reported
as a transient GeV gamma-ray source by the Agile and the Fermi Observatories.
Satisfactory description of the gamma-ray spectra observed from Cyg X-3 are
obtained in the case of the injection of electrons in the inner part of the jet
(located within 300 inner disk radius from the jet base) provided that the
observer is located at relatively small angle to the jet axis.
View original:
http://arxiv.org/abs/1109.1978
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