Spectrum of jet emitting disc: Application to microquasar XTE J1118+480

Abstract

Under the framework of the magnetized accretion ejection structures, we analyze the energy balance properties, and study the spectral energy distributions (SEDs) of the Jet Emitting Disc (JED) model for black hole X-ray transients. Various radiative processes are considered, i.e. synchrotron, bremsstrahlung, and their Comptonizations, and external Comptonization of radiation from outer thin disc. With these cooling terms taken into account, we solve the thermal equilibrium equation self-consistently and find three solutions, of which the cold and the hot solutions are stable. Subsequently we investigate the theoretical SEDs for these two stable solutions.We find the hot JED model can naturally explain the spectra of the Galactic microquasars in their hard states. As an example, we apply this model to the case of XTE J1118+480.