The molecular gas in the circumnuclear region of Seyfert galaxies

Subarcsecond IRAM Plateau de Bure millimeter interferometric observations o f the (CO)-C-12 (2-1) line emission in the Seyfert 1 galaxy NGC 3227 and in the Seyfert 2 galaxy NGC 1068 have revealed complex kinematic systems in t he inner 100-300 pc that are not consistent with pure circular motion in th e host galaxies. Modeling of these kinematic systems with elliptical orbits in the plane of the host galaxy (representing gas motion in a bar potentia l) is a possible solution but does not reproduce all the features observed. A better description of the complex kinematics is achieved by circular orb its that are tilted out of the plane of the host galaxy. This could indicat e that the thin circumnuclear gas disk is warped. In the case of NGC 1068, the warp model suggests that at a radius of similar to 70 pc, the gas disk is oriented edge-on, providing material for the obscuration of the active g alactic nucleus. The position-velocity diagrams show rising rotation curves at r less than or equal to 13 pc and an indication for large enclosed mass es of greater than or equal to 2 x 10(7) M. for NGC 3227 and greater than o r equal to 10(8) M. for NGC 1068 within the central 25 pc.