The circumnuclear environment of NGC613: a nuclear starburst caught in
  the act?
  We present near-infrared ($H$- and $K$-band) integral-field observations of
the inner $\sim$700pc of the active spiral galaxy NGC613, obtained with SINFONI
on the Very Large Telescope. We use emission-line ratios to determine the
dominant excitation mechanisms in different regions within our field-of-view,
in particular the active nucleus and the star-forming circum-nuclear ring.
Diagnostic diagrams involving [FeII] and H$_2$ fluxes indicate that the gas is
not only photoionized by the AGN in the nucleus of NGC613, but also
shock-heated. On the other hand, the emission line ratios measured in the ``hot
spots'' along the ring are fully consistent with them being young star forming
regions. We find no sign of radial gas transport from the ring into the core
region dominated by the AGN. The ring morphology appears disturbed by a radial
outflow of material from the AGN, which is confirmed by the existence of a weak
jet in archival radio maps. However, this jet does not seem to have any
significant effect on the morphology of the large ($\sim$8$\times$10$^7$ solar
masses) reservoir of molecular gas that has accumulated inside the central
$\sim$100pc. Such a concentration of molecular gas around an AGN is unusual,
and supports a scenario in which star formation is recurrent and episodic in
spiral galaxies. In this context, NGC613 appears to be in final stages of the
gas accumulation phase, and is likely to undergo a nuclear starburst in the
near future.
