NGC 4102: High Resolution Infrared Observations of a Nuclear Starburst
  Ring
  The composite galaxy NGC 4102 hosts a LINER nucleus and a starburst. We
mapped NGC 4102 in the 12.8 micron line of [NeII], using the echelon
spectrometer TEXES on the NASA IRTF, to obtain a data cube with 1.5" spatial
and 25 km/s spectral, resolution. Combining near-infrared, radio, and the
[NeII] data shows that the extinction to the starburst is substantial, more
than 2 magnitudes at K band, and that the neon abundance is less than half
solar. We find that the star formation in the nuclear region is confined to a
rotating ring or disk of 4.3" (~300 pc) diameter, inside the Inner Lindblad
Resonance. This region is an intense concentration of mass, with a dynamical
mass of ~3 x 10^9 solar masses, and of star formation. The young stars in the
ring produce the [NeII] flux reported by Spitzer for the entire galaxy. The
mysterious blue component of line emission detected in the near-infrared is
also seen in [NeII]; it is not a normal AGN outflow.
