Central Rotation Curves of Galaxies

We emphasize the use of high-resolution CO line observations to derive central rotation curves of galaxies. We present an example for high-resolution interferometer observations of NGC 3079, and discuss the PV diagram and derived rotation curve. The CO central rotation curves are combined with the outer curves from \ha and HI-line observations to obtain total RC. We show that well resolved RCs for massive galaxies generally start from non-zero velocities at the nucleus.