A 100-kiloparsec wind feeding the circumgalactic medium of a massive
  compact galaxy
  Ninety per cent of baryons are located outside galaxies, either in the
circumgalactic or intergalactic medium. Theory points to galactic winds as the
primary source of the enriched and massive circumgalactic medium. Winds from
compact starbursts have been observed to flow to distances somewhat greater
than ten kiloparsecs, but the circumgalactic medium typically extends beyond a
hundred kiloparsecs. Here we report optical integral field observations of the
massive but compact galaxy SDSS J211824.06+001729.4. The oxygen [O II] lines at
wavelengths of 3726 and 3729 angstroms reveal an ionized outflow spanning 80 by
100 square kiloparsecs, depositing metal-enriched gas at 10,000 kelvin through
an hourglass-shaped nebula that resembles an evacuated and limb-brightened
bipolar bubble. We also observe neutral gas phases at temperatures of less than
10,000 kelvin reaching distances of 20 kiloparsecs and velocities of around
1,500 kilometres per second. This multi-phase outflow is probably driven by
bursts of star formation, consistent with theory.
