A Rapidly Changing Jet Orientation

rapidly_changing_jet_orientation.jpgPowerful relativistic jets are one of the primary ways in which accreting black holes provide kinetic feedback to their surroundings. Jets launched from or redirected by the accretion flow that powers them are expected to be affected by the dynamics of the flow, which for accreting stellar-mass black holes has shown evidence for precession due to frame-dragging effects that occur when the black-hole spin axis is misaligned with the orbital plane of its companion star. Recent theoretical simulations have suggested that the jets can exert an additional torque on the accretion flow, although the interplay between the dynamics of the accretion flow and the launching of the jets is not yet understood. In this contribution, Miller-Jones et al. report a rapidly changing jet orientation—on a time scale of minutes to hours—in the black-hole X-ray binary V404 Cygni, detected with the Very Long Baseline Array during the peak of its 2015 outburst. The authors demonstrate that this changing jet orientation can be modelled as the Lense–Thirring precession of a vertically extended slim disk that arises from the super-Eddington accretion rate. These findings suggest that the dynamics of the precessing inner accretion disk could play a role in either directly launching or redirecting the jets within the inner few hundred gravitational radii. Similar dynamics should be expected in any strongly accreting black hole whose spin is misaligned with the inflowing gas, both affecting the observational characteristics of the jets and distributing the black-hole feedback more uniformly over the surrounding environment.

Image: Artist's concept, V404 Cygni. The binary star system consists of a normal star in orbit with a black hole. Material from the star falls towards the black hole and spirals inwards in an accretion disk, with powerful jets being launched from the inner regions close to the black hole. Credit: ICRAR

Publication: James C.A. Miller-Jones (International Centre for Radio Astronomy Research – Curtin University)  et al., A Rapidly Changing Jet Orientation in the Stellar-mass Black-hole System V404 Cygni, Nature, 569, 374 (29 April 2019).

NRAO Press Release: Black Hole's Tug on Space Pulls Fast-Moving Jets in Rapid Wobble

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