Doppler-shifted X-ray emission lines from highly-ionized atoms, appearing together with radio emission from the relativistic jets of the black-hole candidate X-ray binary 4U 1630-47, indicate that the X-ray emission lines arise in a jet travelling at approximately two-thirds the speed of light and imply that the jet contains baryons.
- María Díaz Trigo
- James C. A. Miller-Jones
- Tasso Tzioumis