  We have derived rotation curves of nearby galaxies, which are almost
completely sampled from the inner to outer regions. We used high-resolution
position-velocity diagrams in the CO line along the major axes for the inner
regions, and HI-line data for the outer regions. We combined the CO and HI data
to obtain total rotation curves from the nuclear to outer regions. The rotation
curves show a steep nuclear rise within a radius smaller than the resolutions
of CO-line observations, indicating a compact massive concentration near the
nucleus. We show that the nuclear steep rise is general and universal, and a
rigid body-like gentle rise is exceptional.
  Keywords: Galaxies: kinematics - Galaxies: rotation - Galaxies: structure -
Galaxies: general - ISM: CO emission - ISM: HI gas
