The Galactic Centre Chimney
  Evidence has increasingly mounted in recent decades that outflows of matter
and energy from the central parsecs of our Galaxy have shaped the observed
structure of the Milky Way on a variety of larger scales. On scales of ~15 pc,
the Galactic centre has bipolar lobes that can be seen in both X-rays and
radio, indicating broadly collimated outflows from the centre, directed
perpendicular to the Galactic plane. On far larger scales approaching the size
of the Galaxy itself, gamma-ray observations have identified the so-called
Fermi Bubble features, implying that our Galactic centre has, or has recently
had, a period of active energy release leading to a production of relativistic
particles that now populate huge cavities on both sides of the Galactic plane.
The X-ray maps from the ROSAT all-sky survey show that the edges of these
cavities close to the Galactic plane are bright in X-rays. At intermediate
scales (~150 pc), radio astronomers have found the Galactic Centre Lobe, an
apparent bubble of emission seen only at positive Galactic latitudes, but again
indicative of energy injection from near the Galactic centre. Here we report
the discovery of prominent X-ray structures on these intermediate
(hundred-parsec) scales above and below the plane, which appear to connect the
Galactic centre region to the Fermi bubbles. We propose that these
newly-discovered structures, which we term the Galactic Centre Chimneys,
constitute a channel through which energy and mass, injected by a
quasi-continuous train of episodic events at the Galactic centre, are
transported from the central parsecs to the base of the Fermi bubbles.
