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.
Results
Showing 1 to 20 of 100 for “"Multi-wavelength"”.
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Multi-wavelength observations of sprites over southern Africa
… in 2017/2018. Sprites were observed using multiple cameras that were filtered at specific wavelengths. In 5 out of 65 nights of observations, 113 video frames containing one or more sprites were recorded, comprising different morphologies (Carrot-single (10%), Carrot/Column (10%), …
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Low coherence fibre interferometry with a multi-wavelength light source
This thesis describes the results of study of the multi-wavelength low coherence fibre interferometry. The development and performance of the all-fibre interferometric measurement systems utilising multi-wavelength combination sources are described. Principal aspects of the low-coherence sensor …
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High-resolution multi-wavelength study of the jet in 3C273
… Telescope at infrared, optical and ultraviolet wavelengths. These observations reveal a flattening of the high-frequency spectrum of the jet, a surprising feature which cannot be accounted for by any single-population synchrotron model. Both the observed flattening of the high-frequency spectrum …
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Multi-wavelength study of neutron stars in the Magellanic Clouds
Massive stars are essential drivers of galaxy evolution, as well as the synthesis of heavier elements, enriching the interstellar and intergalactic medium with metals through every cycle of star formation. Thus to understand the evolving universe, it is essential to quantify the formation and …
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Decoding Continuous Gravitational Waves from Pulsars: A Multi-Wavelength Approach
… data analysis techniques and the integration of multi-wavelength observations. The research presented in this thesis focuses on developing, applying, and refining methodologies to detect CW signals using data from ground-based GW detectors and Imaging Atmospheric Cherenkov Telescopes (IACTs). In …
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Three-Dimensional Microscopy by Laser Scanning and Multi-Wavelength Digital Holography
… The method, based on the simultaneous dual-wavelength digital holography, allows for higher axial range at which the unambiguous phase imaging can be performed. The technique is capable of nanometer axial resolution. The noise level, which increases as a result of using two wavelengths, is …
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Multi-Wavelength Extragalactic Surveys: Star Formation of IR-Submm Selected Galaxies
… regime, I carried out a comprehensive multi-wavelength approach at the North and South Ecliptic Poles (NEP/SEP). I explore four different methods to select high-z galaxies identifying a new sample of Dusty Star-Forming Galaxies (DSFGs) producing a legacy catalogue for future …
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South African Astronomical Observatory data archiving for multi-wavelength astronomy research
… be located, compared, and retrieved, combining multispectral and multiple instrument data from different archives to show the evolution of data interoperability across wavelengths. The diverse methods applied and the organisation of resources and collaboration between different facilities to …
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Multi-wavelength, multi-beam, photonic based sensor for object discrimination and positioning
… is much more sensitive to vibrations than a multi-beam stationary optic approach. Mirror device scanners are slow, bulky and expensive and being inherently mechanical they wear out as a result of acceleration, cause deflection errors and require regular calibration. Multi-wavelength laser …
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Comparative aerosol studies based on multi-wavelength Raman LIDAR at Ny-Ålesund, Spitsbergen
The Arctic is a particularly sensitive area with respect to climate change due to the high surface albedo of snow and ice and the extreme radiative conditions. Clouds and aerosols as parts of the Arctic atmosphere play an important role in the radiation budget, which is, as yet, poorly quantified …
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Microphysical retrieval of non-spherical aerosol particles using regularized inversion of multi-wavelength lidar data
… for our purposes, capable of performing multiple-dataset inversions and producing a wide range of microphysical retrieval outputs. Hybrid regularization in conjunction with minimization processes is used as a basis for our algorithms. Synthetic data retrievals are performed simulating …
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Very high energy emission and multi-wavelength campaigns of the BL Lac object PKS 2155-304.
This thesis is concerned with multi-wavelength observations of the prominent southern hemisphere high energy BL Lac object, (HBL), PKS 2155-304. After a general introduction covering the particulars of Active Galactic Nuclei, the pysical processes and models that are believed to play an important …
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Investigating the nature of Peculiar Supernovae and Fast Radio Bursts via their multi-wavelength properties and environments
… origins, prompting ongoing research into their multi-wavelength properties and environments. FRBs are powerful, millisecond-long bursts of radio waves from outside the Milky Way Galaxy. At the same time, some supernovae—particularly SLSNe—are much brighter than standard models predict, and their …
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Formation of young massive star clusters: a high-resolution multi-wavelength study of intensely star-formation galaxies
Super star clusters (SSCs) represent the youngest and most massive form of known gravitationally bound star clusters in the Universe. They are born abundantly in environments that trigger strong and violent star formation (SF) such as in galaxy mergers and interacting systems. SSCs are thus used as …
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A multi-wavelength study of the dwarf galaxies NGC 2915 and NGC 1705 : star formation, gas dynamics and dark matter
This thesis presents the results of a detailed multi-wavelength study of the nearby blue compact dwarf galaxies NGC 2915 and NGC 1705. The primary data set (nearly 100 hours of on-source data) for each galaxy consists of new observations of the neutral hydrogen (Hi) line obtained with the Australia …
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Probing the role of environment and HI content in galaxy evolution: a multi-wavelength study of isolated and paired galaxies
… which, when incorporated into a cohesive multi- wavelength study, provide important clues as to how Hi forms, influences, and is processed in galaxies. These are the studies informing our theories for galaxy evolution, providing the incentive for superior telescopes (e.g. SKA), and …
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The broad spectral energy distributions of accreting white dwarfs
… Variable stars (CVs) are excellent examples of multi-wavelength objects. They have been detected at all frequencies, from radio to γ-ray. However, while large sets of multi-wavelength data exist, few studies have been performed on the broad spectral energy distributions (SEDs) of these objects. …
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