Central Kinematics and Rotation Curve of the Sb Galaxy NGC 4527 in CO, Hα and [N II] Lines

We have obtained interferometer observations of the central region of the Sb galaxy NGC 4527 in the CO (J = 1–0) line emission using the Nobeyama Millimeter Array. We also obtained optical (Hα, [N II]) spectroscopy using the Okayama 188-cm reflector along the major axis. The kinematical structure and the distribution of H II regions show symmetry around the nucleus, while the distribution of molecular gas is asymmetric. The molecular-gas mass shares only 10% of the dynamical mass in the central 1 kpc radius region. Using position-velocity diagrams, we have derived a center-to-disk rotation curve. It rises steeply in the central region, attaining a maximum of about 250 km s⁻¹ at 400 pc radius, and then decreases to a minimum at 2 kpc radius, followed by a disk and outer flat part. The rotation curve may provide us with the most similar case to that of the Milky Way Galaxy.