Robert Andrew Knop

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 Pa-beta, narrow Pa-beta, and narrow [Fe II] (lambda = 1.2567 micron) emission lines are identified in the spectrum. Additionally, a spatially unresolved narrow component probably due to [S ix] (lambda = 1.25235 micron) is observed on the nucleus. The narrow Pa-beta and [Fe II] lines are observed to be extended over a scale of 5 sec. The spatial variation of the velocity centers of the Pa-beta 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 Pa-beta emission line along the full spatial extent of the observed emission. This result suggests that despite the correlation between the bulk kinematics of Pa-beta and [Fe II], there is an additional process, perhaps fast shocks from a wind in the Seyfert nucleus, contributing to the [Fe II] emission.

Spatially Resolved Near-Infrared Spectroscopy of the Seyfert 2 Galaxies Markarian 1066, NGC 2110, NGC 4388, and Markarian 3

We present near-infrared spectra with resolutions of λ/Δλ ~ 1200 in the emission lines Paβ, [Fe II] (λ = 1.2567 μm), Brγ, and H2 ν = 1–0 S(1) of the nuclei and circumnuclear regions of the four Seyfert 2 galaxies Mk 1066, NGC 2110, NGC 4388, and Mk 3. All of these galaxies show strong near-infrared line emission that is detected at radii several times the spatial resolution, corresponding to projected physical scales of 0.07 to 0.7 kpc. Velocity gradients are detected in these nuclei, as are spatial variations in line profiles and flux ratios. We compare the spatial and velocity distribution of the line emission to previously observed optical line and radio emission. The evidence indicates that the [Fe II] emission is associated with the Seyfert activity in the galaxies. Our data are consistent with X-ray heating being responsible for most of the [Fe II] emission, although differences in [Fe II] and Paβ line profiles associated with radio emission suggests that the [Fe II] emission is enhanced by fast shocks associated with radio outflows. The H2 emission is not as strongly associated with outflows or ionization cones as is the emission in other lines, but rather appears to be primarily associated with the disk of the galaxy.

VV 114, a high infrared luminosity interacting galaxy system

VV 114 is a nearby example of a far-infrared (FIR) bright, high luminosity (L(sub FIR) greater than 10(exp 11) solar luminosity) interacting galaxy pair. At a redshift of z = 0.02 it provides an opportunity to study such interacting galaxies at a favorable spatial scale (390 pc/arcsec). This paper presents new high resolution near-infrared (1.25 to 3.7 micrometer) and visible images, and visible spectra of VV 114. A picture emerges of a system with widespread massive star formation throughout both interacting galaxies. The brighter visible galaxy (VV 114W) shows H II region-like emission in both visual spectra and near-infrared colors, with no more than two magnitudes of visual extinction. The brightest peak of infrared and radio emission (VV 114E) has extreme near-infrared colors and is located at a minimum of visible emission. This indicates a large concentration of dust in the nucleus of VV 114E that is nearly entirely obscuring a major luminosity source in this system.