Jets from X-ray binaries

1 Contents 9 Jets from X-ray binaries page 1 9.1 History 2 9.2 Physical properties of the jets 3 9.3 Ubiquity 14 9.4 Disc–jet coupling in black hole binaries 15 9.5 Disc-jet coupling in neutron star binaries 26 9.6 High energy / particle emission from jets 29 9.7 Interactions 32 9.8 Relation to other jet sources 34 9.9 On the origin of jets 36 9.10 Conclusions 39 Bibliography 40 9.1 History Relativistic outflows, or 'Jets', represent one of the most obvious, important and yet poorly-explained phenomena associated with accreting relativistic objects, including X-ray binaries. Originally recognised in images as long, thin structures apparently connected at one end to the nuclei of galaxies, it was soon established that they represent powerful flows of energy and matter away from accreting black holes and back to the Universe at large. From their earliest association with the most luminous sources in the Universe, the Active Galactic Nuclei (AGN), the conclusion could have been drawn that jets were a common consequence of the process of accretion onto relativistic objects. Nevertheless, their association with the analogous accretion processes involving stellar-mass black holes and neutron stars was not systematically explored until the past decade or so. Although it is now clear that the electromagnetic radiation from X-ray binary jets may extend to at least the X-ray band, historically the key observational aspect of jets is their radio emission. High brightness temperatures (see section 9.2), 'nonthermal' spectra and polarisation measurements indicate an origin as synchrotron emission from relativistic electrons. Following the discovery of luminous binary X-ray sources in the 1960s and 1970s, radio counterparts were associated with the brightest of these, e.g. Sco X-1 (Hjellming & Wade 1971a), Cyg X-1 (Hjellming & Wade 1971b) and the outbursting source Cyg X-3 (Gregory et al. 1972 et seq.). However, it was not until 2 9.2 Physical properties of the jets 3 radio observations of the strong radio source associated with the unusual binary SS 433 revealed a resolved radio source that the field of X-ray binary jets really opened up (Spencer 1979; see also Hjellming & Johnston 1981a,b). Outbursts of 'soft X-ray transients' were also often associated with strong, transient radio emission (e.g. In the 1990s the study of jets from X-ray binaries entered a new phase with the discovery of apparent superluminal motions in the outflow from the bright X-ray transient 'microquasar' For the first time it was clear …