Pair Annihilation and Radio Emission from Nova Muscae
  In the hard X-ray spectra of some X-ray binaries line features around 500 keV are detected. We interpret these as arising from pair annihilation in relativistic outflows leading to a significant Doppler shift of the frequencies of the lines. We show that a small fraction of pairs escaping the annihilation region may give rise to the radio synchrotron emission observed in Nova Muscae 1991. 
D.C. Hannikainen (1,2) and C.R. Kaiser (2) ((1) Observatory,   University of Helsinki, Finland, (2) Department of Physics & ...