"August 2001." / Includes bibliographical references (p. 308-311). / iii, 311 p. : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Describes the use of optical telescopes in the investigation of astronomical objects which have been discovered by earth-orbiting high-energy astronomical satellites. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2002?

Thesis (Ph. D.)--University of California, San Diego, 1984. / Vita. Includes bibliographical references (leaves 141-142).

Thesis (Ph. D.)--University of California, San Diego, 1984. / Vita. Includes bibliographical references (leaves 141-142).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 110-113). Available also in a digital version from Dissertation Abstracts.

No description available.

Thesis (Ph. D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2002? / "August 2001." Includes bibliographical references (p. 308-311).

Thesis (Ph. D.)--University of Chicago, Dept. of Astronomy and Astrophysics, August 1999. / Includes bibliographical references. Also available on the Internet.

Certain restrictions associated with conventional photographic techniques have led to the use of a low light level television tube (isocon tube) as an alternative detector for astronomical spectra. An on-line digital data acquisition system has been developed to process and analyze data from the television camera. The digital system consists of a high speed analog-to-digital converter, a digital computer with magnetic tape transport and oscilloscope display, and some digital control logic. Spectra displayed on the photocathode of the isocon tube are digitized by the A/D converter and stored on magnetic tape via the computer processor. Data acquisition time for one frame of data (1360 samples) is less than 1.5 seconds. Results obtained with the system indicate that it performs as initially intended and is able to resolve spectral features of the order of 0.1 mm. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

An explanation of the emission line behavior in cataclysmic variables has been among the most important and elusive problems in eruptive star research. This work expands accretion disk chromosphere models of line emission to predict line behavior qualitatively. A search for UX UMa-like thick disk cataclysmics in the Palomar Green survey sample gave space densities consistent only with luminous high accretion rate disks: Ṁ ≥ 10⁻⁷·⁰Mₒ/yr. Instead, 20 composites whose combined energy distributions were "flat", Fᵥ α ν⁰, were discovered. These typically were early K dwarfs paired with 30,000K subdwarf O stars. The study also showed that a substantial fraction of subdwarf O and B stars are binary. The detached eclipsing binary BE UMa showed a reflection effect emission line spectrum due to the close 7Rₒ separation between an EUV-emitting subdwarf O star and an M1-5 dwarf. Analysis gave the hot star physical parameters as: 80,000K ≤ T(p)(K) ≤ 100,000, 7.0 ≤ log g(p) ≤ 8.0, and log (He/H) = 1.0 ± 1.0. The BE UMa optical emission line spectrum was modeled using a quantitative photoionization-recombination stellar atmosphere-like code. A rich high excitation continuum fluorescence and recombinational spectrum including HeII λ4686 and CIII λ4650 was formed at lower optical depths corresponding to nₑ ≤ 10¹³·⁵ cm⁻³ and Tₑ = 20,000K. The model suggests that T(p) = 100,000K. Cataclysmic variables too have a central source due to loss of half the accretion energy at the white dwarf surface. This temperature is no higher than the innermost disk regions; hence, mass accretion rates determine the character of the EUV radiation. Observations of 13 cataclysmics representing most types were obtained. From these data, the H, HeI, HeII, CaII, and high excitation metal emission line behavior in cataclysmics were analyzed. Cataclysmic variable accretion rates were shown to follow a sequence; from the low excitation dwarf novae [10⁻⁹·⁵ ≤ Ṁ (Mₒ/yr) ≤ 10⁻⁸·⁵] to the high excitation novae and nova-like systems [10⁻⁸·⁵ < Ṁ(Mₒ/yr) ≤ 10⁻⁶·⁵]. Predicted line profiles were consistent with observations. Thus, the model accounts well for the considered observations.

No description available.