Which gamma-ray space telescope discovered the Milky Way's Fermi bubbles?

The gamma-ray space telescope that discovered the Milky Way’s Fermi bubbles was the Fermi Gamma-ray Space Telescope.

The bubbles are two enormous lobes of high-energy emission extending above and below the Galactic Center. They were announced in 2010 after scientists used data from Fermi’s Large Area Telescope to separate the structure from the diffuse gamma-ray glow that fills much of the sky. Each lobe stretches roughly 25,000 light-years from the center.

Their origin is still debated. The bubbles may record powerful activity from Sagittarius A* millions of years ago, or they may have been produced by intense bursts of star formation and supernovae near the Galactic Center. Their sharp edges and combined gamma-ray and X-ray emission make them an important clue to the Milky Way’s energetic history.

Fermi was launched in 2008 under the name GLAST, the Gamma-ray Large Area Space Telescope, and was renamed for physicist Enrico Fermi later that year. INTEGRAL, Swift, and the Compton Gamma Ray Observatory also study high-energy phenomena, but Fermi’s all-sky gamma-ray observations revealed this particular Galactic structure.