Radio luminosity at  ~9 GHz versus 3 − 9 keV X-ray luminosity for the BH candidates GX 339 − 4, H 1743-322 and V404 Cyg during their hard X-ray states, together with the atoll-type NS binaries Aql X-1 and 4U 1728-34 during their island states (see footnote 2 for details on the data). The radio/X-ray luminosity correlation with b ~ 0.6 for BH binaries and b ~ 1.38 for island state NS binaries is also reported. The positions of XSS J1227 at the three distances 1 kpc, 2.4 kpc, and 3.6 kpc are marked in red. Adapted from Coriat et al. (2011). (See electronic version for colour figure.)