Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 110-116). Available also in a digital version from Dissertation Abstracts.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 59-63). Also available in electronic version. Access restricted to campus users.

This dissertation addresses the co-evolutionary relationship between central super-massive black holes and host galaxies. This relationship is suggested by observed correlations between black hole mass (M[subscript BH]) and properties of the host galaxy bulge. We first discuss investigation of the relationship between MBH and host galaxy velocity dispersion, [sigma subscript asterisk], for quasars in the Sloan Digital Sky Survey (SDSS). We derive MBH from the broad emission line width and continuum luminosity, and [sigma subscript asterisk] from the width of narrow forbidden emission lines. For redshifts z < 0.5, our results agree with the locally-observed M[subscript BH]- [sigma subscript asterisk] relationship. For 0.5 < z < 1.2, the M[subscript BH]- [sigma subscript asterisk] relationship appears to evolve with redshift in the sense that bulges are too small for their black holes. Part of this apparent trend can be attributed to observational biases, including a Malmquist bias involving the quasar luminosity. Accounting for these biases, we find approximately a factor of two evolution in the M[subscript BH]- [sigma subscript asterisk] relationship between the present and redshift z [approximately equal] 1. The second topic involves a search for the largest velocity dispersion galaxies in the SDSS. Black holes in quasars can have M[subscript BH]exceeding 5 billion M[mass compared to the sun], implying [sigma subscript asterisk] > 500 km s−1 by the local M[subscript BH]- [sigma subscript asterisk] relationship. We present high signal-to-noise HET observations for eight galaxies at redshift z < 0.3 from the SDSS showing large [sigma subscript asterisk] while appearing to be single galaxies in HST images. The maximum velocity dispersion we find is [sigma subscript asterisk] = 444 km s−1, suggesting either that quasar black hole masses are overestimated or that the black hole - bulge relationship changes at high black hole mass. The third topic involves work contributed to co-authored papers, including: (1) evidence for recoiling black holes in SDSS quasars, (2) the [sigma][O III] - [sigma subscript asterisk] relationship in active galactic nuclei (AGN), and (3) accretion disk temperatures and continuum colors in quasars. Lastly, we discuss research in progress, including: (1) possible physical influences on the width of narrow emission lines of SDSS AGN, including the gravitational effect of the black hole, and (2) a search for binary AGN in the SDSS using double-peaked [O III] emission lines. / text

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Orbit-based modeling is a powerful way to construct dynamical models of galaxies. It has been used to measure the masses of supermassive black holes (SMBHs), constrain dark matter halos, and to recover information about the orbit structure of galaxies. This type of modeling usually goes hand in hand with the study of elliptical galaxies, however its applicability extends much further than this. In this thesis, I apply the well-studied technique of orbit-based modeling to two different types of galaxies—NGC 4594 (Sa) and Fornax (dSph). In NGC 4594, I use orbit-based models to update the mass of the central SMBH, place new constraints on its dark matter halo, and analyze the internal moments of its distribution function. For Fornax, the focus is to determine the shape of the dark matter density profile as well as to learn what we can from the internal moments. / text

No description available.

The role of ice blocks in the creation of distinctive proglacial landscapes during and following glacier outburst floods (jökulhlaups) In recent years, it has been recognised that ice blocks form a major component of jökulhlaups. There are, however, very few published hypotheses of ice-block impact during and following jökulhlaups. The November 1996 jökulhlaup in southern Iceland, which transported ice blocks as large as 55 metres in diameter on to Skeioarärsandur, provided an opportunity to study ice-block impact produced during a high-magnitude flood. This thesis aims to (i) determine the impact of ice blocks on the morphology and sedimentology of proglacial river channels during and following a jökuihlaup, and (ii) provide a model which links distinctive landscapes created by ice blocks with specific controls on ice-block impact. A range of ice-block related features are produced during and following a jökulhlaup reflecting glacial and topographical constraints, ice-block characteristics and jökulhlaup hydraulics. In locations where sediment flux remains high throughout a flood, large ice blocks form kettle-scours. Rapid sediment deposition around ice blocks results in the formation and preservation of antidune stoss sides, entirely aggradational ice block obstacle shadows and hummocky topography. The grounding of ice blocks in flows of low sediment concentration or total exhumation of buried ice blocks results in the formation of classic U-shaped obstacle marks. Where channel geometry abruptly expands ice-block berms form. On outwash fans kettle holes and obstacle marks occur in distinct clusters. 11 Kettle holes form post-flood by the in situ melt of (1) progressively buried ice blocks and (2) small ice blocks incorporated into flow deposits. Ice block debris is superimposed onto obstacle marks and kettle holes and deposited on the post-flood streambed to form rimmed kettle holes and obstacle marks and ice-block till mounds respectively. Knowledge of associations between ice blocks and the bedforms and facies produced during and following a jökulhlaup will aid jökulhlaup identification and reconstruction in modern and ancient proglacial environments.

Extensions to general relativity are often considered as possibilities in the quest for a quantum theory of gravity on one hand, or to resolve anomalies within cosmology on the other. Scalar fields, found in many areas of physics, are frequently studied in this context. This is partly due to their manifestation in the effective four dimensional theory of a number of underlying fundamental theories, most notably string theory. This thesis is concerned with the effects of scalar fields on cosmological and black hole solutions. By comparison, an analysis of an inhomogeneous cosmological model which requires no extensions to general relativity is also undertaken. In chapter three, examples of numerical solutions to black hole solutions, which have previously been shown to be linearly stable, are found. The model includes at least two scalar fields, non-minimally coupled to electromagnetism and hence possesses non-trivial contingent primary hair. We show that the extremal solutions have finite temperature for an arbitrary coupling constant. Chapter four investigates the effects of higher order curvature corrections and scalar fields on the late-time cosmological evolution. We find solutions which mimic many of the phenomenological features seen in the post-inflation Universe. The effects due to non-minimal scalar couplings to matter are also shown to be negligible in this context. Such solutions can be shown to be stable under homogeneous perturbations. Some restrictions on the value of the slope of the scalar coupling to the Gauss-Bonnet term are found to be necessary to avoid late-time superluminal behaviour and dominant energy condition violation. A number of observational tests are carried out in chapter five on a new approach to averaging the inhomogeneous Universe. In this "Fractal Bubble model" cosmic acceleration is realised as an apparent effect, due to quasilocal gravitational energy gradients. We show that a good fit can be found to three separate observations, the type Ia supernovae, the baryon acoustic oscillation scale and the angular scale of the sound horizon at last scattering. The best fit to the supernovae data is χ² ≃ 0:9 per degree of freedom, with a Hubble parameter at the present epoch of H0 = 61:7+1:4 -1:3 km sec⁻¹ Mpc⁻¹ , and a present epoch volume void fraction of 0:76 ± 0:05.

Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 143-156). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 117-140). Also available via the World Wide Web.