Excited molecular hydrogen around the Seyfert nuclei of NGC 3227 and 4151

High-resolution images of the nuclear regions of the Seyfert galaxies NGC 3227 and 4151 have been obtained in the H_2 1-0 S(1) emission line (rest lambda = 2.1218 mu m) with the IRCAM3 camera on the 3.8-m UKIRT telescope. A 2" elongation of the photoexcited H_2 is observed in NGC 3227 that is coincident with the optical nucleus. Combined with other observations, this indicates the presence of a molecular disc surrounding the active nucleus with the interior being photoexcited. A 2 x 2.5 arcsec^2 ring of excited H_2 centred on the nucleus is partially observed in NGC 4151. This is believed to be part of a circumnuclear torus that contains ionized, atomic and molecular gas in an onion-skin structure....