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Investigations into cosmology and astronomy.

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Payne, Andrew David 1969 , 'Investigations into cosmology and astronomy.', PhD thesis, University of Tasmania.

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Abstract

The thesis begins with a short review of tensor analysis and
general relativity. Only those equations which have direct
application to cosmology are considered in any detail. The analyses
throughout this thesis are based on the metric for homogeneous and
isotropic space-times, defined by the Robertson-Ilalker line element.
The classification of relativistic world-models containing
both matter and radiation is considered in some detail. The
properties of some model parameters are determined as a function of
the temperature of the radiation field which is assumed to be
Planckian. Some attention is also given to the problems of event
and particle horizons in uniform world-models.
Data derived from radio source observations are used extensively
in an attempt to solve the cosmological problem. The distribution of
source angular diameters with redshift and the variation of source
average spectral index with redshift (or luminosity) both provide
useful information on the evolutionary properties of the universe.
The radio source counts of the recent 5C survey are examined for their
cosmological implications. The analysis provides important evidence
on the epoch corresponding to galaxy formation and the variation with
time (or more directly with expansion parameter) of source luminosity
or density in co-ordinate volume. Arguments are given supporting a
rapidly expanding evolutionary universe in which the matter density
is somewhat greater than usually accepted values.
The effect of free-free absorption by intergalactic ionized
hydrogen on the low frequency spectra of radio galaxies is examined
for the steady-state, adiabatic and constant temperature universes.
Using thermodynamic principles, a differential equation is
derived which determines the temperature path of the intergalactic
gas in evolutionary universes. The gas is assumed to be heated by
cosmic rays and plasma waves, and cooled by radiative losses and
expansion of co-ordinates.
An integral equation is obtained for the extragalactic background
intensity when intergalactic absorption is present. The
radio background spectrum is determined for the steady-state,
"adiabatic" and constant temperature models of the universe. In
each case the theoretical spectrum is compared with the observed
background spectrum.
The extragalactic component of the sky brightness is calculated
by using the differential equation describing the thermal history of
the intergalactic gas and the cosmological parameters derived from
the source counts. The calculations include the separate cases of
source luminosity evolution and source density evolution.
The diffuse X-ray flux is described in terms of Compton
radiation from cosmic ray electrons in intergalactic space. The
electrons are assumed to be ejected from radio galaxies in a time
which is small compared with the characteristic time of evolution
of the universe. Normalisation of the derived X-ray spectra yield
estimates for the intergalactic cosmic ray energy density.
Finally a mathematical treatment is given which describes the
consequences of the introduction of a general vector field into
Einstein's field equations. The theory is applicable to universes
of arbitrary intrinsic curvature. Some tentative conclusions are
drawn concerning possible annihilation of matter.

Item Type: Thesis - PhD
Authors/Creators:Payne, Andrew David
Keywords: Cosmology, Astronomy
Copyright Holders: The Author
Copyright Information:

Copyright the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).

Additional Information:

Includes bibliographical references. Thesis (Ph.D.) - University of Tasmania, 1969.

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