In galaxies with an active supermassive black hole, astronomers often see twin jets erupting from their center. These jets typically spew outward into space in opposite directions. But in the galaxy PKS 2014-55, about 800 million light-years from Earth, the jets coming from its central supermassive black hole don’t act like this. Instead, this galaxy — and other “X-galaxies” like it — appears to have four jets forming the shape of an “X.”
The reason why X-galaxies have such strange shapes was previously unknown. But thanks to new detailed MeerKAT observations, astronomers have found the explanation. PKS 2014-55’s X-shaped jets of radio waves, which extend 2.5 million light-years into space, are being turned back onto the galaxy as they encounter the pressure of intergalactic gas. But as the material falls back toward the center of the galaxy, it’s deflected by higher gas pressure near the center and instead curves outward, creating the horizontal arms of the X.
The paper has been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.