The nuclear gas disk of NGC 1566 dissected by SINFONI and ALMA
  We present the results of near-infrared H- and K-band European Southern
Observatory SINFONI integral field spectroscopy of the Seyfert galaxy NGC 1566.
We investigate the central kpc of this nearby galaxy, concentrating on
excitation conditions, morphology, and stellar content. NGC 1566 was selected
from our NUGA (-south) sample and is a ringed, spiral galaxy with a stellar
bar. We present emission and absorption line measurements in the central kpc of
NGC 1566. Broad and narrow Br{\gamma} lines were detected. The detection of a
broad Br{\gamma} component is a clear sign of a super-massive black hole in the
center. Blackbody emission temperatures of ~1000 K are indicative of a hot dust
component, the torus, in the nuclear region. The molecular hydrogen lines,
hydrogen recombination lines, and [FeII] indicate that the excitation at the
center is coming from an AGN. The central region is predominantly inhabited by
molecular gas, dust, and an old K-M type giant stellar population. The
molecular gas and stellar velocity maps both show a rotation pattern. The
molecular gas velocity field shows a perturbation toward the center that is
typical for bars or spiral density waves. The molecular gas species of warm
H_2(1-0)S(1) and cold ^{12}CO(3-2) gas trace a nuclear gas disk of about 3" in
radius with a nuclear spiral reaching toward the nucleus. From the equivalent
width of H_2(1-0)S(1) a molecular ring with r<~3" can be inferred. This spiral
seems to be an instrument that allows gas to fall toward the nucleus down to
<50 pc scales. The excitation of molecular hydrogen in the nuclear gas disk is
not clear but diagnostic diagrams show a distinction between the nuclear region
and a <9 Myr old star forming region at the southwestern spiral arm. Possibly
shocked gas is detected ~2" from the center, which is visible in dispersion
maps of H$_2$(1-0)S(1) and ^{12}CO(3-2) and in the 0.87 mm continuum.
