  We have obtained high-resolution position-velocity (PV) diagrams along the
major axes of the central regions of nearby galaxies in the CO-line emission
using the Nobeyama 45-m telescope and the Millimeter Array. Nuclear rotation
curves for 14 galaxies have been derived based on the PV diagrams using the
envelope-tracing method. The nuclear rotation curves for most of the galaxies
show a steep rise within a few hundred pc, which indicates a high-density
concentration of mass.
  Keywords: Galaxies: general - Galaxies: structure - ISM: molecular line
