Spatially Resolved Infrared Spectroscopy of Seyfert Galaxies

Citation

Knop, Robert A., Jr. (1997) Spatially Resolved Infrared Spectroscopy of Seyfert Galaxies. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/GZ2H-3X10. https://resolver.caltech.edu/CaltechTHESIS:05302018-084028309

Abstract

This thesis presents infrared spectroscopy of the circumnuclear regions of 23 Seyfert galaxies. Observations are spectrally resolved with a resolution of λ/Δλ ~ 1000 and spatially resolved to ~ 1", corresponding to ~ 10² pc for the objects in the sample. The instrument used for the observations, the Palomar Near-Infrared Spectrometer, is described, and problems peculiar to reduction of data from it are discussed. The lines observed include Paβ, Brγ, [FeII] (λ=l.2567μm), and H₂ (λ=2.1213μm). In nine objects, the coronal line [SIX] (λ=l.2524μm) is also detected. Spatially resolved line emission is clearly visible in approximately half of the objects observed. The data for five of the objects showing the best spatially resolved infrared line emission are analyzed in detail. These objects include Seyfert 1.5 galaxy NGC 4151 and Seyfert 2 galaxies Mk 1066, NGC 2110, NGC 4388, and Mk 3. The data for the remaining objects is presented in tabular form, and each object is discussed briefly. The data argue that processes associated with the Seyfert nucleus are responsible for the bulk of the observed [FeII] emission. Kinematic and spatial associations can be drawn between features in the [FeII] line profiles and other processes associated with the active nucleus, such as outflows seen in ionized optical emission and radio lobes. Most of the [FeII] appears to emerge from partially ionized regions excited by nuclear x-rays, with an additional contribution from fast shocks. Some of the H₂ emission also appears to be associated with the nuclear activity. However, in some cases the H₂ emission is observed to have a different spatial distribution from [FeII] and the H⁺ emission. The H₂ emission is probably thermally excited. No significant differences are found between the infrared line emission of Seyfert and Seyfert l.x galaxies.

Thesis Files