What produces the extended LINER-type emission in the NUGA galaxy NGC
  5850?
  (Abridged) The role of low ionization nuclear emission region (LINER)
galaxies within the picture of active galactic nuclei (AGN) has been
controversial. It is still not clear whether they host an AGN in a low
accretion mode, or whether they are not active at all but dominated by
alternative ionization mechanisms, namely shocks, winds/outflows, or
photoionization by a post asymptotic giant branch (p-AGB) stellar population.
The detection of extended LINER-like emission was often taken as evidence of
ionization by stellar components but this has not been undisputed. We performed
optical integral field spectroscopic observations on the central approx. 4 kpc
of NGC 5850 using VIMOS at the VLT, which provides spatially-resolved spectra
for the gas emission and the stellar continuum. We derive and analyse emission
line and kinematic maps. We find the central few kpc of NGC 5850 to be
dominated by extended LINER-like emission. The emission-line ratios that are
sensitive to the ionization parameter increase with radial distance to the
nucleus. Therefore, the extended LINER-like emission in NGC 5850 is dominated
by ionization from distributed ionization sources, probably by stars on the
p-AGB. The LINER-like region is surrounded by emission that is classed as
'composite', likely due to a mixture of a LINER-like ionization pattern and
photoionization by low-level star formation. Two star-forming regions are
present in the 21"x19" field of view. One of them is located approximately in
the ring surrounding the kinematically decoupled core. The second one is close
to the nucleus and is the origin of a region of decreased emission line ratios
oriented radially outwards. We find the interstellar gas to have areas of steep
velocity gradients and a complex kinematic morphology, probably caused by the
lopsided (m=1) distribution of the gas. The inflow of gas toward the center
appears possible.
