NASA's Fermi Telescope Finds Giant Structure in our Galaxy
Here's the preprint announcing the discovery: Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?.
These bubbles are gigantic and may have been created by an episode of Galactic center activity 1-2 Mya Fermi Bubbles: Evidence for a Possible Recent AGN Jet Activity in the Galaxy.
On the other hand maybe they are really, really old! The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays