That's where photons literally move around the black hole, and around that is this hot gas that's drawn to the black hole, and it's hot because of friction.
As it comes out here then, you've got this hot high pressure gas that comes along this tube, snakes its way all the way around, up and down and up and down.
All the hot gases in the flames are way hotter than the air around them, which causes them to rise, which is why flames always go up and seem pointed at the top.
The background galaxies show that there's a lot of matter, shown here in violet, centered on the two clusters, but it's clearly not the hot gas seen by Chandra, and is giving off no light.