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Abstract

Extra-solar X-ray astronomy started in 1962 with the detection of Sco X-1 and the
galactic center during a rocket flight designed to find lunar X-rays. Since then,
mainly as a result of a series of dedicated satellite missions the number of known
(until 1984) X-ray sources had increased to about 1000. This number is
comparable to the number stars brighter than 4th magnitude. The X-ray sky at this
sensitivity appears as crowded as a moonlit night. The most comprehensive
catalogue is that from the HEAO-1 satellite (1977/1978). This catalogue (Wood et
al. 1984) lists 842 sources at energies below 20 keV. Unlike optical wavelengths
about half the brightest soft to medium energy X-ray sources are associated with
extra-galactic objects which are either galaxy groups or active galactic nuclei (AGN
eg. Quasars, Seyfert, BL Lac). Fainter AGN may make up the bulk of the diffuse
X-ray background. The galactic objects are mainly binary stars containing either a
white dwarf or neutron star. The rest are stars with enhanced solar-like activity.
The number of known X-ray sources is set to increase to about 100,000 ( much the
same as number of stars visible with binoculars) with the completion of the present
ROSAT survey. In a twist of history, one of the early ROSAT images actuality
showed the moon.

Item Type:	Thesis - PhD
Authors/Creators:	Dieters, Stefan W. B.(Stefan William Boyd)
Keywords:	X-ray astronomy
Copyright Holders:	The Author
Copyright Information:	Copyright 1990 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 (p. 308-328)
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