Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 37 for “"F500 - Astronomy"”.
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The spatial distribution of metals in disc galaxies, via simulations and observations
In this thesis we are interested in the evoluNon of disc galaxies. One of the most common ways to study it is by a deep analysis of the distribuNon of chemical abundances in the stellar populaNons of the disc component. Abundance gradients let us reconstruct the puzzle of the formaNon and evoluNon …
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Optical and X-ray studies of newly discovered flare stars
Results are presented demonstrating that selection of dMe flare stars from their EU V/optical flux ratio revealed some of the most active members from the ROSAT Wide Field Camera (WFC) and EUVE all-sky surveys. During a total photometric monitoring time of 121 hrs on 6 new stars, there were 54 …
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A multi-frequency study of symbiotic stars
Multi-frequency observations using a wide variety of telescopes and instrumentation have been used to throw light upon some of the physical characteristics of symbiotic stars. A detailed understanding of these enigmatic binaries requires the planning of large, simultaneous observing campaigns to …
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The development and application of an astronomical imaging and photometric CCD system
… selected areas of interest to the Department of Astronomy at the University of Central Lancashire, was to be assessed. Initially the principles of operation of CCD cameras were reviewed, a suitable CCD system purchased and a camera operating program developed by modification of the original …
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Modelling the balmer line profiles in the spectra of symbiotic stars
The Balmer emission lines in the spectra of symbiotic stars are often seen to have a double-peaked morphology when observed at high resolution. In this respect, they bear striking similarities to the Balmer line profiles in the spectra of cataclysmic variables, (Cv's) where their origin is ascribed …
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Photometric monitoring of early type emission line stars
A programme of simultaneous optical (UBVRI) and infrared (JHKL MNQ) photometry of early type, emission line, stars is described. Particular emphasis is placed on observations of suspected pre-main-sequence objects such as Herbig Ae/Be stars. The observations, together with data from the IRAS point …
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Infrared to millimetre observations of active galaxies
This thesis presents measurements of the continuum emission at infrared (IR) to millimetre wavelengths from the nuclear regions of a number of active galaxies. In particular many observations have been made for the first time in the submillimetre regime. The observing methods at these wavelengths …
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Amplitude modulation and energy conservation of pulsation modes in delta Scuti stars
The pulsations in δ Sct stars are excited by a heat engine driving mechanism caused by in-creased opacity in their surface layers, and have pulsation periods of order a few hours. Space based observations in the last decade have revealed a diverse range of pulsational be-haviour in these stars, …
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Effects of solar particle events on Geospace
The Earth receives all of its external energy input from the Sun (except for galactic sources), which consists of both particles of various energies and electromagnetic radiation of various wavelengths. The particles emitted from the Sun constitute the solar wind, from which the interplanetary …
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A knowledge base approach to the specification of non-functional real-time system requirements
During the late seventies it became necessary to partition the system development life-cycle into layers of conceptualisation and abstraction to provide enhanced information hiding and thus a smoother transition from specification to implementation. The existence of system requirements analysis as …
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A study of the plasmaspheric electron content using satellites of the global positioning system
The upper atmosphere of the Earth is ionised by electromagnetic radiation and energetic charged particles emanating from the Sun. The ionisation forms the ionosphere of heavy ions (e.g. O) and electrons between about 70 and several hundred kilometres above the Earth's surface. Above this, the …
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Large Quasar Groups at Redshift ~ 2
This project aims to use the large public databases that are now becoming available in the Virtual Observatory. For my purpose two of the most important datasets for investigating Large Quasar Groups (LQGs) are the Sloan Digital Sky Survey (SDSS) and the 2dF Quasar Redshift Survey (2QZ). These have …
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Made-to-measure Modelling of Nuclear Star Clusters
The nuclear star clusters of late-type spiral galaxies are comprised of multiple components. Gemini near-infrared spectroscopy of the nuclear star cluster in NGC 4244 shows clear rotation. Earlier, De Lorenzi et al. (2013) constructed two component (disc + spheroid) axisymmetric three integral …
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Kinematics and Stellar Populations in Brightest Cluster Galaxies
This thesis is devoted to the investigation of a new, large sample of brightest cluster galaxies (BCGs), their kinematic and stellar population properties and the relationships between these and the properties of the host clusters. Some of the questions addressed are: how the kinematic and stellar …
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The Galaxy Environment of Quasars in the Clowes-Campusano Large Quasar Group
Quasars have been used as efficient probes of high-redshift galaxy clustering as they are known to favour overdense environments. Quasars may also trace the largescale structure of the early universe (0.4 1< z <1 2) in the form of Large Quasar Groups(LQGs), which have comparable sizes (r.J …
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Millimetre and Submillimetre continuum imaging studies of nearby active galaxies
The thesis presents millimetre (mm) and submm continuum imaging observations of the four, nearby active galaxies Cygnus A, NCC 4374, Centaurus A and M 82. These were undertaken using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope in Hawaii. The study …
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Extreme Ultraviolet Spectroscopy of the Solar Corona
New Extreme Ultra-Violet (EUV) observations of the solar corona, obtained by the Coronal Diagnostic Spectrometer (CDS) instrument on board the NASA/ESA Solar and Heliospheric Observatory (SOHO) are presented. The CDS instrument for the first time has provided the opportunity of observing a large …
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The Structure and Dynamic nature of the Solar Atmosphere
This thesis presents an examination of a range of dynamic phenomena present throughout the solar atmosphere, from the photosphere to the corona. Above the photosphere, where the plasma fi is small, the emitting plasma structure and dynamics are tied intimately to the solar magnetic field. Firstly, …
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The Cluster and Large Scale Environments of Quasars at z < 0.9.
We present an investigation into the environments of quasars with respect to galaxy clus- ters, and environment evolution with redshift and luminosity. The positions of quasars with respect to clusters have been studied using cluster and quasar catalogues available, covering the redshift range 0.2 …
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Cosmological Simulations of Galactic Disc Assembly
We address the issue of kinematic heating in disc galaxies by analysing a suite of cosmological Milky Way-type disc simulations run with different particle-and grid-based hydrodynamical codes and different resolution, and compare them with observations of the Milky Way. By studying the kinematics …
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