Rotation curve and dynamical mass in the inner region of M100 with ALMA

Using Atacamma Large Millimeter/Submillimeter Array (ALMA) science verification data, the CO J=1→0 emission in the nucleus of barred SABbc spiral galaxy M100 (which also known as NGC 4321) has been drawn at high resolution (3.44" × 2.46"). A new (Position - Velocity) diagram of the central (1 kpc) region of the mentioned galaxy has been analyzed to study the peculiar kinematics of this region. The CO data which fully sampled at this resolution, by using fixed position angle PA=153°, it is found that the rotation curve that is rapidly rising in the central (100 pc) reaching value (160 km/s) at (480 pc) and then decrease smoothly to a value (144 km/s) in the outermost ring at (750 pc). The inner region has dynamical mass of 3·7 × 10
⁹
M
_⊙
in central 720 pc region.