Migliari, Simone

Doppler-shifted lines revealing baryons in the jets of the X-ray binary 4U 1630-47.

Author list: S. Migliari, M. Diaz, J. Miller-Jones, W. Broderic, T. Tzioumis

Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies.  The power carried away by the jets, and hence the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. While energetic considerations and circular polarisation measurements have provided conflicting circumstantial evidence for the presence or absence of baryons, the only system in which baryons have been directly detected in the jets is the X-ray binary SS 433.  We report the detection of Doppler-shifted X-ray emission lines from the black hole X-ray binary 4U1630-47, coincident with the reappearance of radio emission from the jets of the source.  We argue that these lines arise in a jet with velocity 0.66c, thereby establishing the presence of baryons in the jet.