Instantaneous jet power measured in an accreting black hole

Nature Astronomy, Published online: 30 April 2026; doi:10.1038/s41550-026-02829-2 For a black hole X-ray binary system, the deflection of its radio jets by the stellar wind has been measured across an entire orbit. By balancing the momentum flux of the jets and the wind, the instantaneous kinetic power of the jet is determined and its value vindicates standard assumptions from cosmological simulations.