Spied through a normal telescope, the galaxy PKS 2014-55 is an unremarkable smudge of bright light. But look again in radio wavelengths, and you'll see that the galaxy is hiding a gargantuan, glowing treasure at its center — and X marks the spot.
The sky is full of weird X-shaped galaxies. Here's why.
Spied through a normal telescope, the galaxy PKS 2014-55 is an unremarkable smudge of bright light. But look again in radio wavelengths, and you'll see that the galaxy is hiding a gargantuan, glowing treasure at its center — and X marks the spot.
PKS 2014-55 is an X-shaped radio galaxy (XRG), an unusual type of galaxy that looks like an enormous X in the night sky when imaged in radio wavelengths. The long arms of the X — each one about 100 times longer than the Milky Way — are actually a blazing-fast soup of particles and magnetic fields, blasted out of the galaxy's central black hole and traveling for millions of light-years into space, far beyond the galaxy's edge.
Big jets of radio energy are common in galaxies with hungry black holes at their centers (even the Milky Way has two "bubbles" of radio energy around its gut). However, most of those jets come in orderly pairs that appear to form a straight line or a round bulge when seen from far away. According to William Cotton, an astronomer at the National Radio Astronomy Observatory (NRAO) in Virginia who studies XRGs, fewer than 10% of known cosmic radio sources take on a distinct X shape like this one.