The origin of the near-IR line emission from molecular, low and high
  ionization gas in the inner kiloparsec of NGC6240
  The understating of the origin of the H2 line emission from the central
regions of galaxies represent an important key to improve our knowledge about
the excitation and ionization conditions of the gas in these locations. Usually
these lines can be produced by Starburts, shocks and/or radiation from an
active galactic nucleus (AGN). Luminous Infrared Galaxies (LIRG) represent
ideal and challenging objects to investigate the origin of the H2 emission, as
all processes above can be observed in a single object. In this work, we use
K-band integral field spectroscopy to map the emission line flux distributions
and kinematics and investigate the origin of the molecular and ionized gas line
emission from inner 1.4x2.4 kpc2 of the LIRG NGC6240, known to be the galaxy
with strongest H2 line emission. The emission lines show complex profiles at
locations between both nuclei and surrounding the northern nucleus, while at
locations near the southern nucleus and at 1" west of the northern nucleus,
they can be reproduced by a single gaussian component. We found that the H2
emission is originated mainly by thermal processes, possible being dominated by
heating of the gas by X-rays from the AGN at locations near both nuclei. For
the region between the northern and southern nuclei shocks due to the
interacting process may be the main excitation mechanism, as indicated by the
high values of the H2l2.12um/Brg line ratio. A contribution of fluorescent
excitation may also be important at locations near 1" west of the northern
nucleus, which show the lowest line ratios. The [FeII]l2.072um/Brg ratio show a
similar trend as observed for H2l2.12um/Brg, suggesting that [FeII] and H2 line
emission have similar origins. Finally, the [CaVIII]l2.32um coronal line
emission is observed mainly in regions next to the nuclei, suggesting it is
originated gas ionized by the radiation from the AGN.
