Broadband Emission Spectra from the Cygnus X-3 Jet in the Soft Spectral State

Abstract: In order to understand the main observational characteristics of the Galactic X-ray binary Cygnus X-3, we propose a radiation model in which high-energy electrons accelerated in the dissipation zone of a jet produce the non-thermal broadband emissions. Broadband spectral energy distributions are computed to confront with the AGILE and\emph{ Fermi} LAT data together with the multi-band data, during soft X-ray spectral states. By fitting observations at different locations of the jet, we find that the emission region is rather compact and should be located at the distance of about one orbital radius. Our results can explain the current multi-frequency observations and also predict the TeV band emission. The model could be tested by a polarization measurement at IR band, and/or by a correlation study between the GeV and TeV bands once very high-energy observations are available.