Infrared Spectroscopy of Pa(Beta) and [Fe II] Emission in NGC 4151

We present spatially resolved 1.24-1.30 micron spectroscopy with a resolution of 240 km/s of the Seyfert 1.5 galaxy NGC 4151. Broad Paβ, narrow Paβ, and narrow [Fe II] (λ = 1.2567 microns) emission lines are identified in the spectrum. Additionally, a spatially unresolved narrow component probably due to [S IX] = (λ = 1.25235 microns) is observed on the nucleus. The narrow Paβ and [Fe II] lines are observed to be extended over a scale of 5". The spatial variation of the velocity centers of the Paβ and [Fe II] lines show remarkable similarity, and additionally show similarities to the velocity structure previously observed in ground based spectroscopy of [O III] emission in NGC 4151. This leads to the conclusion that the [Fe II] emission arises in clouds in the Seyfert narrow line region that are physically correlated with those narrow line clouds responsible for the optical emission. The [Fe II] emission line, however, is significantly wider than the Paβ emission line along the full spatial extent of the observed emission. This result suggests that despite the correlation between the bulk kinematics of Paβ and [Fe II], there is an additional process, perhaps fast shocks from a wind in the Seyfert nucleus, contributing to the [Fe II] emission.