Thesis (Ph. D.) in Physics--University of Maine, 2000. / Includes vita. Includes bibliographical references (leaves 149-153).

No description available.

Thesis (Ph. D.)--University of Hawaii at Manoa, 2002. / Includes bibliographical references. Also available on microfiche.

No description available.

Optical imaging polarimetry has been performed on seven nearby Seyfert galaxies, three with face-on and four with edge-on host galaxies of various morphological classifications. Observations in V, R, B and H(_a) wavebands are presented as maps of total intensity and of polarized intensity, overlaid with polarization vectors. Independent determinations of the interstellar polarization (ISP) contribution from our own galaxy are made where possible, and are used to produce ISP corrected maps. The polarization patterns seen in the maps show evidence of either dichroic extinction, which indicates the presence of non-spherical dust grains in large-scale galactic magnetic fields, or scattering, which is due to the illumination of regions of dust grains or electrons. The polarization features, which are observed at the different wavebands, are then compared to recent models of polarization in external galaxies. Estimates of the intrinsic Seyfert nuclear polarization are made where possible by correcting for ISP and for an approximation of the dilution due to the host galaxy flux by using values from previous studies. Both the measured and the corrected nuclear polarizations are compared with previously published values, and are discussed in the context of the standard models of Seyfert galaxies. Most of the observed galaxies show evidence of polarization, both from the host galaxy and from the intrinsic Seyfert nucleus. In particular, distinct polarization features: bands of polarization consistent with extended dusty disks aligned with the dusty tori proposed in Seyferts, and regions of polarization corresponding to scattering of the nuclear continuum along the biconical extended Seyfert emission-line regions, have been identified in several of the observed galaxies.

The objective of this dissertation is twofold. Firstly an extensive yet concise literature review on the state-of-the-art of near infrared barred spiral galaxy classi cation is presented. Secondly, two quantitative approaches to galaxy classi cation at near infrared wavelengths, the relative gravitational torque method and the isophotal ellipse tting method, are applied for the rst time to a sample of selected Spitzer IRAC nearby barred galaxies. Maximum relative gravitational torques are derived for a sample of 40 nearby bright barred disk galaxies at 3.6 m and 4.5 m. These torques are compared between galaxy pairs at these passbands and we nd an excellent agreement between the 3.6 m and 4.5 m morphology. The sample used incorporates a wide range of inclination and bar strength values. The tight coupling of 3.6 m and 4.5 m morphology provides an opportunity to classify intermediate redshift galaxies that have their near-infrared rest frame emissions shifted red-ward to 4.5 m; i.e.: out to z = 0:25. We nd a greater frequency of higher maximum relative torques in our sample compared with either Block et al. (2002) or Buta et al. (2004) due to sample bias, as this dissertation is aimed at understanding quantitative methods in classifying barred galaxies. Furthermore, we compare results from applying an isophotal ellipse tting technique and a gravitational torque analysis to a common sample of 28 nearby barred S4G/Spitzer galaxies imaged at 3.6 m. These two quantitative bar strength methods are applied to images that have identical orientation and deprojection parameters for an objective comparison. We nd a strong correlation between the gravitational torque and isophotal ellipse tting methods which in principle supports a method for estimating bar potentials out to intermediate redshifts by using an isophotal ellipse tting approach. This has important implications for bar-fraction estimates and galaxy accretion/evolution scenarios.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: W.E. Harris. Includes bibliographical references (p. 127-132).

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiv, 86 p.; also includes graphics. Includes bibliographical references (p. 83-86).

Thesis (Doctoral)--Rijksuniversiteit Groningen, 1999. / Includes bibliographical references (p. 153-155).

The relationship first pointed out by Tully and Fisher between the luminosity of spiral galaxies and their maximum rotation velocity, as measured by the 21 cm line-width, continues to be one of the best methods available to measure relative distances. At infrared wavelengths, the observational scatter about this relation is typically 0.35 to 0.50 magnitudes, permitting relative distance estimates with an accuracy of about 20 percent. The Malmquist bias in a magnitude-limited sample is 1.38σ ², and while the solution to the general problem is complex, it is clear that reducing the scatter about the Tully-Fisher relation by even a factor of two would make a large difference in our ability to determine the local velocity field from distances and velocities of individual galaxies. In this dissertation we discuss the scatter in the Tully-Fisher relation at infrared wavelengths, and look for ways to reduce that dispersion through the inclusion of additional observational parameters. The data for this study are derived from a CCD survey of 244 spiral galaxies in twenty clusters falling in the redshift range 3,000 to 11,000 km s⁻¹. From surface brightness profiles and elliptical aperture photometry, we obtained isophotal and total magnitudes at B, R, and I, isophotal diameters, mean and nuclear surface brightnesses, and a concentration parameter indicative of the bulge-to-disk ratio. These quantities were then combined with colors and HI-content measures taken from the literature in a search for correlations with Tully-Fisher residuals. None of the trial second-parameters resulted in a substantial decrease in the scatter about the fiducial Tully-Fisher relation. An examination of the properties of the cluster samples shows that many of the clusters exhibit considerable substructure. While it is possible that the implied depth effects are important to the scatter about the magnitude/line-width relation, calculated lower limits to the dispersion in depth turn out to be rather small.