1999MNRAS.305..319F

High-resolution images of the nuclear regions of the Seyfert galaxies NGC 3227 and 4151 have been obtained in the H₂ 1-0 S(1) emission line (rest λ = 2.1218 µ m) with the IRCAM3 camera on the 3.8-m UKIRT telescope. A 2" elongation of the photoexcited H₂ 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 2x2.5 arcsec² ring of excited H₂ 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.