NEUTRAL HYDROGEN STUDIES OF THE SEYFERT-GALAXY NGC-3227

We have used the VLA to image the neutral hydrogen emission from the S eyfert galaxy NGC 3227, with angular resolutions ranging from 12 to 60 arcsec. We detect plumes of HI extending to similar to 70 kpc north a nd similar to 31 kpc south of the galaxy which may be a consequence of interaction. Complex motions in the galactic disc have been resolved into emission from the disc, which is in approximate solid body rotati on, and an anomalous velocity cloud, situated north-west of the disc a t the base of the northern plume. The cloud has a mean velocity of sim ilar to 150 km s(-1) above the systemic velocity of NGC 3227 and shows evidence of rotation. We suggest that this cloud is a gas-rich dwarf galaxy that either is one of the bodies responsible for the interactio n, or has formed as a consequence of the interaction. No neutral hydro gen emission is associated with the companion galaxy NGC 3226, and the presence of low velocity (500 km s(-1)) gas reported in single dish m easurements is not detected in the present observations. The continuum image of NGC 3227 shows an extended component, in addition to the com pact core, that may be enhanced disc emission due to the interaction. In the central 15 arcsec of the disc we detect evidence of HI absorpti on against the nuclear continuum source. Higher resolution observation s are required to confirm this. Although the velocities in the disc ar e remarkably close to solid body velocities (considering the presence of a disturbing companion), the integrated neutral hydrogen emission s hows a bar of enhanced emission crossing the nucleus, in a north-west to south-east direction, that has a 'Z' shaped morphology and trails i n the same sense as the optical spiral arms. This HI bar seems to be a continuation of the CO bar and we suggest that it may play an importa nt role in the fuelling of the AGN. From our HI observations we deduce a heliocentric systemic velocity of 1135 +/- 10 km s(-1) for NGC 3227 . We derive a value of 56 degrees for the inclination of the galactic disc and 158 degrees +/- 2 degrees for the PA of the major arris. Neut ral hydrogen masses of 5.7 x 10(8) M. for the disc, 2.1 x 10(8) M. for the cloud, 1.3 x 10(8) M. in the southern plume and 1.8 x 10(8) M. in the northern plume were found, resulting in a total H I mass for NGC 3227 of 1.1 x 10(9) M..