NGC 1275 is a weird galaxy. It’s a giant elliptical and sits at the center of the Perseus Cluster of galaxies; a kind of megalopolis of galaxies. It sports a gigantic black hole in its heart that belches out enormous bubbles of gas, which drag tendrils of cooler gas thousands of light years out from its core (yes, black holes can eject material as well as gobble it down).
But these tendrils have been a problem for astronomers: they’re very narrow (only a couple of hundred light years wide), have masses a million of times that of the Sun, and should fall apart rapidly (they’re blasting out into hot gas which should disrupt them, they’re massive enough to collapse under their own weight to form stars, and tides from the galaxy itself should shred them). Yet they seem at least semi-stable, lasting for hundreds of millions of years. What holds them together?
Turns out it’s that old standby, magnetism. Recently released Hubble images (like the one above) have given astronomers insight into the structure of these tendrils. Hubble’s hi-res view shows details previously unseen in the tendrils, allowing astronomers a better view and the ability to determine the magnetic strengths needed to hold the tendrils together against the forces that would rend them asunder.
Magnetism is a very important topic in astrophysics (despite some pseudoscientists lying and saying this force is ignored), but it’s not well-understood. It’s fiendishly complex, so much so that it’s a joke in astronomy: when giving a colloquium about an astronomical object’s weird features, saying it’s due to magnetism will always get a chuckle out of an audience. And it’s a standard joke that if you want to derail a talk, ask the speaker about the effects of magnetism. In three dimensions, magnetism is ferociously difficult to model.
But these fantastic images of tendrils show that magnetism is still a major player in galactic dynamics, and if we want to understand the effects of this long-reaching force, we may need to get comfortable in its loving arms. Or tentacles.