The ionised gas outflow in the Circinus galaxy: kinematics and physical
  conditions
  We employ MUSE/VLT data to study the ionised and highly ionised gas phases of
the feedback in Circinus, the closest Seyfert 2 galaxy to us. The analysis of
the nebular emission allowed us to detect a remarkable high-ionisation gas
outflow beyond the galaxy plane traced by the coronal lines [Fe VII]
$\lambda$6089 and [Fe X] $\lambda$6374, extending up to 700 pc and 350 pc NW
from the nucleus, respectively. This is the first time that the [Fe X] emission
is observed at such distances from the central engine in an AGN. The gas
kinematics reveals expanding gas shells with velocities of a few hundred km
s$^{-1}$, spatially coincident with prominent hard X-ray emission detected by
Chandra. Density and temperature sensitive line ratios show that the extended
high-ionisation gas is characterized by a temperature reaching 25000 K and an
electron density > 10$^2$ cm$^{-3}$. We found that local gas excitation by
shocks produced by the passage of a radio jet leads to the spectacular
high-ionisation emission in this object. This hypothesis is fully supported by
photoionisation models that accounts for the combined effects of the central
engine and shocks. They reproduce the observed emission line spectrum at
different locations inside and outside of the NW ionisation cone. The energetic
outflow produced by the radio jet is spatially located close to an extended
molecular outflow recently reported using ALMA which suggests that they both
represent different phases of the same feedback process acting on the AGN.
