In the southern constellation of Circinus (the compass) lies a galaxy with the name ESO 97-G13. At a distance of a mere 15 million light years, it should be one of the most celebrated galaxies in the sky, the equal of the Whirlpool, the Pinwheel, and other big, bright galaxies. But ESO 97-G13, also called the Circinus Galaxy, is relatively unknown. Why?
It's because it lies in the plane of the Milky Way galaxy, and is dimmed to obscurity by all the dust in our galaxy - it's like trying to look out of room filled with smoke. But infrared light can travel through all that junk pretty well, so the view from NASA's Wide-field Infrared Survey Explorer (WISE) is unparalleled.
The galaxy is actually pretty amazing. You can just make out the spiral arms, narrow and long, making a giant S in the sky; those were not seen before WISE took a look. But the picture is dominated by the galaxy's core, which in infrared outshines the rest of the galaxy's light combined. At the nucleus of Circinus is a monster black hole, and matter is spiraling into it. As it does so, it heats up to fantastic temperatures, blasting out X-rays and other forms of energy. This radiation heats up the dust around it - most galaxies are littered with the stuff - which then reradiates that away in the infrared. If you look just outside the intense core, you'll see a ring of light: that's probably where a lot of stars are forming, which again creates more dust that can glow in the IR.
Observatories like WISE open up a new window on the Universe, giving us a view of the sky that we might have otherwise missed... even when something is almost literally right next door.
Image credit: WISE: NASA/JPL-Caltech/WISE Team