[ad_1]
V404 Cygni is a binary system consisting of a black hole and a star in orbit. It is located in the constellation Cygnus at a distance of about 7,800 light-years from Earth. In this type of binary, the material flows from the star to the black hole and collects into an accretion disk, where it is heated, shining at optical wavelengths, UV and X before spiraling into the black hole. Powerful jets are one of the main ways that such black holes provide feedback to their environment. In an article published this week in the journal Nature, astronomers reported a rapid change in jet orientation – on a time scale ranging from minutes to hours – in the Cygni V404 system, detected at the height of its explosion in 2015.
Impression of the artist on the evolution of the orientation of the jets in the V404 Cygni system; each segment (separated by the clock hands) shows the jets at a different time, oriented in different directions, as shown in our high resolution angular radio imagery. Image credit: ICRAR.
The Cygni V404 caught the attention of astronomers for the first time in 1938, when it had an explosion, and it was designated as a "variable star".
Another explosion was observed in 1989 and follow-up studies revealed an unnoticed explosion in 1956.
NASA's Swift satellite detected a new explosion on June 15, 2015, triggering a global observation effort.
"Everyone jumped on the explosion with every possible telescope. So we have this incredible coverage of observation, "said Dr. James Miller-Jones, astronomer of the Curtin University node of the International Center for Research in Radioastronomy.
Dr. Miller-Jones and his colleagues used the observations of the Very Long Baseline Array, a continent-sized radio telescope of 10 satellite dishes scattered across the United States from the Caribbean Virgin Islands to Hawaii.
"This is one of the most extraordinary black hole systems I have ever encountered," said Dr. Miller-Jones.
"Like many black holes, it feeds on a nearby star, moves the gas away from the star and forms a disc of matter that surrounds the black hole and that winds up under it. effect of gravity. "
When astronomers studied the black hole of the Cygni V404, they saw their jets behave like never before.
Where it is generally thought that the jets exit directly from the poles of the black holes, these jets were firing in different directions and at different times. And they changed direction very quickly.
The change in jet movement was due to the V404 Cygni accretion disk.
"The accretion disk is 10 million kilometers wide and the few thousand inner kilometers have been inflated and flickering during the light explosion," said Dr. Miller-Jones.
"The inner part of the accretion disk was actually preceeding and pulling the jets with it."
"You can think of this as a flicker of a spinning top that slows in. Only in this case, this flicker is caused by Einstein's theory of general relativity."
_____
James C. A. Miller-Jones et al. Direction of rapidly changing jets in the V404 Cygni Starhole System. Nature, published online April 29, 2019; doi: 10.1038 / s41586-019-1152-0
[ad_2]
Source link