https://phys.org/news/2018-11-galaxy-scale-fountain-full-glory.html

"The supermassive black hole at the center of this giant galaxy acts like a mechanical 'pump' in a water fountain," said Grant Tremblay, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and lead author on the paper. "This is one of the first systems in which we find clear evidence for both cold molecular gas inflow toward the black hole and outflow or uplift from the jets that the black hole launches."

According to the researchers, this entire system operates via a self-regulating feedback loop. The infalling material provides power for the fountain as it "drains" toward the central black hole, like water entering the pump of a fountain. This infalling gas then causes the black hole to ignite with activity, launching high-velocity jets of super-heated material that shoot out of the galaxy. As it travels, this material pushes out clumps and streamers of gas into the galaxy's expansive halo, where it eventually rains back in on the black hole, triggering the entire process anew.