A Tour of A Tour of NGC 3079 Superbubbles

Narrator (April Jubett, CXC): On Earth, we are familiar with bubbles associated with soap or carbonated water. These bubbles consist of a thin film of liquid enclosing a volume of air or other gas that is only a few inches across. In space, however, bubbles can have very different properties: they are composed of a volume of lighter gas inside a heavier one and they can be huge.

Astronomers have found that the galaxy NGC 3079, located about 67 million light years from Earth, contains two "superbubbles" unlike anything here on our planet. A pair of balloon-like regions stretch out on opposite sides of the center of the galaxy: one is 4,900 light years (or about 30 million billion miles) across. The other is only slightly smaller with a diameter of about 3,600 light years.

The superbubbles in NGC 3079 are defined by X-ray, optical and radio emission. New observations from Chandra show that in NGC 3079 a cosmic particle accelerator is producing ultra-energetic particles in the rims of the superbubbles. These particles can be much more energetic than those created by the world's most powerful accelerators like the Large Hadron Collider.

The superbubbles in NGC 3079 provide evidence that they and structures like them may be the source of extremely energetic cosmic rays, which are not rays but high-energy particles that regularly bombard the Earth. Shock waves — akin to sonic booms caused by supersonic planes — associated with supernova explosions can accelerate particles up to energies about 100 times larger than those generated in the Large Hadron Collider, but astronomers are uncertain about where even more energetic cosmic rays come from. This new result suggests superbubbles may be one source of these ultra-energetic cosmic rays.

NGC 3079's superbubbles are younger cousins of the "Fermi bubbles", first located in the Milky Way galaxy in 2010. Astronomers think such superbubbles may form when processes associated with the infall of matter into a supermassive black hole in the center of galaxy leads to the release of enormous amounts of energy in the form of particles and magnetic fields. Superbubbles may also be sculpted by winds flowing from a large number of young, massive stars.