Nuclear-to-Outer Rotation Curves of Galaxies in the CO and HI Lines
  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 
Yoshiaki Sofue