Gas Cloud Kinematics near the Nucleus of NGC 4151
Gull, T. R.; Kraemer, S. B.; Crenshaw, D. M.; Hutchings, J. B.; Bowers, C. W.; Green, R. F.; Kaiser, M. E.; Hartig, G. F.; Weistrop, D.; Baum, S.; Lindler, D. J.; Hill, G.; Feinberg, L. D.
Canada, United States
Abstract
We report early observations with Space Telescope Imaging Spectrometer (STIS) of the nuclear region of NGC 4151. Direct images in [O II] and [O III] and slitless medium-dispersion spectral images of the Hβ to [O III] region were obtained. A slitless UV spectral image was taken of the C IV 1550 Å region. We present radial velocities and line ratios of ~40 clouds resolved in the narrow-line region (NLR). The kinematics suggest outflow within a biconical region about the nucleus, centered on the radio axis and viewed near the edge of the cones. A few high-velocity clouds are seen that do not fit this simple picture. Line ratios indicate that the NLR gas is photoionized by the central continuum source and that there may be a density gradient in the NLR. These observations are being followed by an extensive STIS program on NGC 4151.
Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555.