Open AccessPair annihilation and radio emission from galactic jet sources: the case of Nova Muscae
Author(s) -
Kaiser Christian R.,
Hannikainen Diana C.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05071.x
Subject(s) - physics , astrophysics , annihilation , nova (rocket) , line (geometry) , astrophysical jet , line of sight , spectral line , astronomy , jet (fluid) , doppler effect , emission spectrum , active galactic nucleus , galaxy , nuclear physics , geometry , mathematics , aeronautics , engineering , thermodynamics
In the hard X‐ray spectra of some X‐ray binaries line features at 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 how this can be used to accurately determine the bulk velocity and orientation to the line of sight of the outflows. Constraints on the energy requirements of such outflows are also derived. Furthermore, we show that a small fraction of pairs escaping the annihilation region may give rise to the radio synchrotron emission observed in some of these objects. We apply these ideas to the hard X‐ray and radio observations of Nova Muscae 1991. In this object, the energy requirements seem to rule out a large proton fraction in the outflows.