National Radio Astronomy Observatory | 2019 Apr 29
Effect of General Relativity explains object's behavior
Jets of fast-moving material shot from the area surrounding a black hole are wobbling so fast that their change in direction can be seen in periods as short as minutes, and astronomers say it’s happening because the rotating black hole’s powerful gravitational pull is dragging nearby space itself along with it. ...
The team studied V404 Cygni, a black hole nine times more massive than the Sun, nearly 8,000 light-years from Earth. The black hole is drawing in material from a companion star with a mass about 70 percent that of the Sun. As the material streams toward the black hole, it forms a rotating disk, called an accretion disk, surrounding the black hole.
In such systems, the disk becomes denser and hotter with decreasing distance from the black hole. Either the innermost portion of the disk or the black hole itself launches jets of material outward away from the disk. The astronomers said V404 Cygni’s jet material moves as fast as 60 percent of the speed of light.
Such a rapid wobble, called precession, as that in V404 Cygni has not been seen before in other such systems. To explain that phenomenon, the scientists said, requires using an effect of Einstein’s general theory of relativity. That theory says that massive objects like black holes distort space and time. Further, when such a massive object is spinning, its gravitational influence pulls space and time around with it, an effect called frame-dragging.
In V404 Cygni, the black hole’s spin axis is misaligned from the plane of its orbit with the companion star. That causes the frame-dragging effect to warp the inner part of the disk, then pull the warped portion around with it. Since the jets originate from either the inner disk or the black hole, this changes the jet orientation, producing the wobbling observed with the VLBA. ...
Spinning black hole sprays light-speed plasma clouds into space
International Center for Radio Astronomy Research (ICRAR) | 2019 Apr 29
Scientists get to the bottom of a 'spitting' black hole
ESA | Space Science | Science & Technology | Integral | 2019 Apr 29
A rapidly changing jet orientation in the stellar-mass black-hole system V404 Cygni ~ James C. A. Miller-Jones et al
- Nature (online 29 Apr 2019) DOI: 10.1038/s41586-019-1152-0