Giant Magnetized Outflows from the Centre of the Milky Way
  The nucleus of the Milky Way is known to harbour regions of intense star
formation activity as well as a super-massive black hole. Recent Fermi space
telescope observations have revealed regions of \gamma-ray emission reaching
far above and below the Galactic Centre, the so-called Fermi bubbles. It is
uncertain whether these were generated by nuclear star formation or by
quasar-like outbursts of the central black hole and no information on the
structures' magnetic field has been reported. Here we report on the detection
of two giant, linearly-polarized radio Lobes, containing three ridge-like
sub-structures, emanating from the Galactic Centre. The Lobes each extend ~60
deg, bear a close correspondence to the Fermi bubbles, are located in the
Galactic bulge, and are permeated by strong magnetic fields of up to 15 \mu G.
Our data signal that the radio Lobes originate in a bi-conical, star-formation
(rather than black hole) driven outflow from the Galaxy's central 200 pc that
transports a massive magnetic energy of ~10^55 erg into the Galactic halo. The
ridges wind around this outflow and, we suggest, constitute a `phonographic'
record of nuclear star formation activity over at least 10 Myr.
