Centaurus A is a giant elliptical radio-galaxy with an active nucleus emitting two very strong radio jets. With a very impressive name to match it's appetite. Oh! And it's also a cannibal.
Munch on that for a bit. Then look look.
The researchers think that in the past Centaurus absorbed a spiral galaxy about the size of the MILKY WAY (i.e. US). Much of the interstellar matter of this spiral galaxy did not just fall into the center of Centaurus A, but rather the densest clouds (of hydrogen gas) were expelled a great distance from the galactic center. Then, the radio jets compressed the gas in the shells, which triggered the formation of new stars recently, enriching the region in heavy elements that can be used as tracers of molecular hydrogen.
And that's how cannibalism works, kids! Yay for science.
Cheers - Martha