"Like the Death Star": jets from black holes can change direction "rapidly"
Supermassive black holes sometimes eject huge streams of matter. It has now been discovered that these can change direction comparatively quickly.
Two black holes with cavities in the surrounding gas
(Image: NASA/CXC/Univ. of Bologna/F. Ubertosi; NSF/NRAO/VLBA; Univ. of Hawaii/Pan-STARRS; NASA/CXC/SAO/N. Wolk)
An international research team has discovered that the powerful jets emitted by some black holes can change direction relatively quickly. Using various instruments, they focused on a total of 16 supermassive black holes and determined that the jets of around a third of them point in a completely different direction than they once did. The researchers compare this to the gigantic Death Star from the Star Wars science fiction universe. However, while the aim there is to destroy planets with the beam, the black holes with their oscillating jets are likely to ensure that fewer stars are formed in the surrounding area.
Consequences for the development of galaxies
The j ets are gigantic streams of matter that are ejected from supermassive black holes in the center of galaxies, sometimes far beyond their boundaries. How exactly this happens is one of the big questions in astronomy. With the help of NASA's Chandra X-ray telescope, the research team has now investigated cavities that have been torn into the surrounding gas by several black holes using such jets. This enabled them to determine that there is apparently a more than 30 percent probability that these jets will change direction significantly. In some cases, this happens after a few million or a few dozen million years. Given that the black holes are billions of years old, this is "fast".
While the causes of the change in direction have so far only been speculated upon, they are likely to have concrete consequences, the team writes. For example, the jets ensure that the interstellar gas cannot cool down sufficiently to allow the extensive formation of stars. As a result, supermassive black holes could slow down the formation of stars in much larger areas of a galaxy than previously thought. At the same time, however, the galaxies are too far away to be able to determine whether the jets swinging around are damaging stars and their planets, the team clarifies. They have presented their work in The Astrophysical Journal.
(mho)