We present new interferometric observations of the ^ { 12 } CO ( 1-0 ) , ^ { 12 } CO ( 2-1 ) , and HCN ( 1-0 ) molecular line emission in NGC 3227 obtained with the IRAM Plateau de Bure interferometer ( PdBI ) .
We achieved an unprecedented angular resolution in the ^ { 12 } CO ( 2-1 ) line of about 0.6 ” corresponding to only about 80 pc at a distance of 17.3 Mpc .
The mapped ^ { 12 } CO emission is concentrated in the inner 8 ” and accounts for 20 % of the total 30 m ^ { 12 } CO line flux .
The ^ { 12 } CO emission is resolved into an asymmetric nuclear ring with a diameter of about 3 ” .
The HCN line emission is mostly unresolved at our resolution of \sim 2.4 ” and contains all of the single dish flux .
We have decomposed the observed molecular gas motions into a circular and non-circular component revealing that about 80 % of the gas in the circum-nuclear region exhibits pure circular rotation .
We find evidence for bar streaming onto the nuclear ring and a redshifted emission knot on the ring perimeter . In the central arcsecond the gas shows apparent counter rotation .
This behavior can be best explained by a warping of the inner molecular gas disk rather than gas motion in a nuclear bar potential .
We detected molecular gas at a distance from the nucleus of only \sim 13 pc with a velocity of about 75 km/s with respect to the systemic velocity and find that within the central arcsecond the rotation curve is rising again .
This is the first time that millimetric CO-line emission has been detected interferometrically at such small distances to the nucleus of a Seyfert galaxy .
These measurements indicate a lower limit on the enclosed mass of about 2 \times 10 ^ { 7 } M _ { \odot } in the inner 25 pc .