May 29, 2015

A team of astronomers using the Hubble Space Telescope found an unambiguous link between the presence of supermassive black holes that power high-speed, radio-signal-emitting jets and the merger history of their host galaxies. Almost all galaxies with the jets were found to be merging with another galaxy, or to have done so recently.
The team studied a large selection of galaxies with extremely luminous centers — known as active galactic nuclei — thought to be the result of large quantities of heated matter circling around and being consumed by a supermassive black hole. While most galaxies are thought to host supermassive black holes, only a small percentage of them are this luminous and fewer still go one step further and form what are known as relativistic jets. The two high-speed jets of plasma move almost at the speed of light and stream out in opposite directions at right angles to the disc of matter surrounding the black hole, extending thousands of light-years into space.