An analysis of the broadband electromagnetic emission of the microquasar GX 339-4

Abstract

The source GX 339-4 is an extensively studied galactic X ray binary. Radio observations have revealed the presence of relativisticjets. In this work we present a jet model that provides good fits to a set ofsimultaneous radio and X-ray observations of GX 339-4. We assume thatrelativistic electrons and protons are present in the jets, and calculateboth the leptonic and hadronic contributions to the radiation producedby several types of particle interactions. We also calculate the electromagneticemission of secondary particles (pions, muons and electron-positronpairs) created in hadronic and electromagnetic interactions, and assessthe relevance of photon self-absorption in the jet. Finally, we estimatethe pair production rate in order to investigate the possible connectionbetween microquasars and the observed anti-matter annihilation line fluxat 511 keV. Our predictions may be tested in the near future with datacollected by the gamma-ray satellite Fermi and the Cherenkov telescopearray HESS II.