Other
Scientific paper
Jan 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994phdt........13n&link_type=abstract
PhD Dissertation, Virginia Univ. Charlottesville, VA United States
Other
4
Seyfert Galaxies, Near Infrared Radiation, Active Galaxies, Velocity Distribution, Cross Correlation, Gravitational Fields, Star Formation Rate, Radio Emission, Nuclear Potential, Luminosity, Spectral Bands, Kinematics
Scientific paper
In this Ph.D. dissertation I present moderate resolution spectroscopy (80-230 km/s FWHM) from two spectral regions, one in the near infrared containing the Ca 11 triplet absorption features, at approximately 8550 A, and the (SIII) lambda 9069 A emission line, and the other in the visual including the Mg b absorption lines, at approximately 5175 Angstrom, and the (OIII) lambda 5007 Angstrom emission line. Nuclear stellar velocities, V*, and velocity dispersions, sigma* were measured using the cross-correlation method. Emission line velocities and widths were also measured from the spectra. I address three basic questions regarding the role played by the host gravitational potential in active galaxies. First, do Seyferts show abnormal nuclear stellar dynamical properties compared to normal galaxies of the same luminosity and Hubble type? Second, to what extent does the nuclear emission line gas share the same velocity field as the stars? Third, do other properties of the narrow line region (NLR), such as radio and emission line luminosities depend on the depth of the nuclear potential as measured by the stellar velocity dispersion? I have found that Seyfert galaxies follow the Faber-Jackson relation indicating essentially normal stellar kinematics. The relationship for Seyferts, however, is offset from that for normal galaxies indicating that Seyferts have lower mean mass-to-light ratios. This may result from higher star-formation rates or simply a tendency for Seyferts to inhabit galaxies with somewhat younger stellar populations. I have also found that the kinematics of emission line gas in the narrow line region are primarily influenced by the host gravitational potential. A number of secondary influences are also identified, including kiloparsec scale linear radio sources and objects experiencing tidal distortions. Correlations linking the radio and emission line luminosities with the depth of the gravitational potential have also been found. Seyferts with larger bulges apparently have stronger NLRs. The strengths of the Mg I b and Ca II triplet lines have also been measured. I have found that the equivalent widths of these absorption lines are at least consistent with dilution by a power law continuum although a young stellar population may also weaken the lines.
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