Feeding Versus Feedback in NGC1068 probed with Gemini NIFS. I.
  Excitation
  We present emission-line flux distributions and ratios for the inner 200pc of
the narrow-line region of the Seyfert2 galaxy NGC1068, using observations
obtained with the Gemini Near-infrared Integral Field Spectrograph (NIFS) in
the J, H and K bands at a spatial resolution of 10pc and spectral resolution of
5300. The molecular gas emission - traced by the K-band H_2 emission lines -
outlines an off-centered circumnuclear ring with a radius of 100pc showing
thermal excitation. The ionized gas emission lines show flux distributions
mostly outlining the previously known [OIII]5007 ionization bicone. But while
the flux distributions in the HI and HeII emission lines are very similar to
that observed in [OIII], the flux distribution in the [FeII] emission lines is
more extended and broader than a cone close to the nucleus, showing a "double
bowl" or `hourglass" structure". This difference is attributed to the fact that
the [FeII] emission, besides coming from the fully ionized region, comes also
from the more extended partially ionized regions, in gas excited mainly by
X-rays from the active galactic nucleus. A contribution to the [FeII] emission
from shocks along the bicone axis to NE and SW of the nucleus is also supported
by the enhancement of the [FeII](1.2570)/[PII](1.1885) and
[FeII](1.2570)/Pabeta emission-line ratios at these locations and is attributed
to the interaction of the radio jet with the NLR. The mass of ionized gas in
the inner 200pc of NGC1068 is MHII~2.2E4 M_Sun, while the mass of the H2
emitting gas is only M_{H2}~29M_Sun. Taking into account the dominant
contribution of the cold molecular gas, we obtain an estimate of the total
molecular gas mass of Mcold~2E7 M_Sun.
