In a recent issue of the journal Nature, an international team of astronomers published an article on the unusual behavior of a jet emanating from the close binary system V404 Cygnus. It is located in the constellation of the same name at a distance of 7800 light years from the Sun.
The V404 Cygnus system consists of a stellar mass black hole and an ordinary star. Due to the proximity, the black hole gradually pulls on the companion's substance. As a result, an accretion disk forms around it. Part of its matter is absorbed by the black hole, and part is thrown out in the form of a jet - a narrow jet of plasma moving at a speed of 60% of the speed of light.
Sometimes V404 Cygnus produces bright flares. During the last burst of activity in 2015, an array of 10 VLBA radio telescopes performed a series of observations of the system. In their course, astronomers discovered an unusual phenomenon: multiple changes in the direction of the jet V404 Cygnus within very short periods of time, measured in minutes.
As a rule, the direction of the jets either does not change, or changes slowly. According to scientists, the unusual behavior of V404 Cygnus is explained by the Lense-Thirring effect. According to General Relativity, it occurs when a rotating massive body drags along with itself space-time. As a result, all objects around are also forced to move in a circle in the same direction.
According to the researchers, in the V404 Cygnus system, the axis of rotation of the black hole is displaced relative to the orbital plane of the companion star. This leads to the fact that the Lense-Thirring effect deforms the inner part of the disk and pulls it along. As a result, a tilted donut-like part is formed in its center. It "swells" due to high heating and radiation pressure, but it is rather small in size. Its diameter is only a few thousand kilometers. Since the jet is formed in the immediate vicinity of the black hole, the tilted inner part “redirects” it in different directions.
Promotional video:
The Lense-Thirring effect is the only mechanism the researchers have been able to suggest to explain the deflections of the V404 Cygnus jet. It is worth noting that while studying the active nuclei of galaxies with supermassive black holes, scientists have already found signs of a change in the direction of the jets. Previously, their behavior was explained by the presence of a second supermassive black hole. But it is possible that we are talking about the same effect.
