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 18 of 18 for “"Milky Way galaxy"”.
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Star Formation History of the Milky Way Galaxy Disk Using a Hierarchical Model
… vital to know the universe's age or that of our Galaxy – the Milky Way, to understand how the universe evolved to its current state. First, the Galactic population must be studied to understand the universe. A well-grounded way to understand the Galactic population is to learn about the white …
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First results from a 20-liter prototype dark matter detector with directional sensitivity
… massive particles in the dark matter halo of the Milky Way galaxy. These detectors are also able to reconstruct the directions of these nuclear recoils, allowing for better rejection of possible background events. This thesis describes the design of a small prototype detector and the strategies …
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Massive stars in low metallicity environments
… verify theoretical models. Recent surveys of the galaxy and Magellanic clouds in addition to continuous development of stellar evolution codes are, however, replenishing the domain of massive stars so that we may probe the characteristics of their evolution to better understand the early stages of …
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Stacking the Gamma-ray Sky to Search for Faint Astrophysical Populations
… from interstellar clouds to the center of the Milky Way Galaxy. Entering the 13th year of its orbit around Earth, the Fermi Space Gamma-ray Telescope has been continually surveying the γ-ray sky with its Large Area Telescope (LAT) on board. The latest Fermi source catalog contains over 6000 …
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Investigating the nature of Peculiar Supernovae and Fast Radio Bursts via their multi-wavelength properties and environments
Transient astronomical sources offer new ways to explore phenomena such as the origins of black holes, fast radio bursts, the nature of supernova explosions, the mechanisms driving gamma-ray bursts, and the role of mergers in producing gravitational waves. Two peculiar classes of transients, fast …
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Chemical abundances in planetary nebulae in NGG 6822
… located in NGC 6822, a Local Group Irregular Galaxy at a distance of .557 Mpcs, were examined using the Richey-Cretien spectrograph and the Silicon Intensified (SIT) Vidicon, on the 4-meter telescope at the Cerro Tololo Interamerican Observatory. From the measurement of selected emission line …
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Dissipative heating and nonthermal distributions in black hole accretion flaring events
The center of the Milky Way galaxy contains a supermassive black hole called Sgr A*, which has been observed at radio, mm, X-ray, and near infrared (NIR) wavelengths. The NIR emission flares about once per day with the flaring state being about an order of magnitude brighter than the non-flaring …
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Signatures of the first stars in relics of the first galaxies
… Indeed, the old dwarf galaxies that orbit our Milky Way galaxy today have descended from the first galaxies and contain stars that retain a remarkably detailed record of their past. In this thesis, I use the chemical abundances of stars in old dwarf galaxies to open a window into the era of …
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Search for Gamma-ray Spectral Lines with the Fermi Large Area Telescope and Dark Matter Implications
… particle (WIMP). Measurements indicate that the Milky Way Galaxy resides in a halo of dark matter, making it an ideal laboratory for investigating these elusive particles. As WIMPs are predicted to be heavy, their interactions should produce high-energy gamma rays that would be detected by the …
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Studies of TeV Gamma-Ray Sources in the Hydrogen-Alpha Optical Line
The first way humanity explored our Milky Way Galaxy and the Universe was through optical light observations. That led us to explore the cosmos using different electromagnetic wavebands such X-rays, gamma-rays, and radio wavelengths. Since then multi-wavelength studies of sources have started to …
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The Cryogenic Dark Matter Search low ionization-threshold experiment
… in which we sit is defined by its abundance. The Milky Way galaxy, hence life, wouldn’t have formed if small over densities of Dark Matter had not caused sufficient accretion of stellar material. Marvelous experiments have been designed based on basic notions to directly and indirectly study Dark …
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The identification and classification of variability in stellar sources observed with SuperWasp
… the presence of the Oosterhoff dichotomy in the Milky Way. During this work, period/amplitude ranges and distribution maps were created for the classified stars in stellar classes Algol, Beta Lyrae, W UMa, Delta Scuti and RR Lyrae (RRAB) and comparison made with published equivalents. SuperW ASP …
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Indigenous approaches to forecasting rainfall for adaptation of Bambara nuts (vigna subterranea) production practices in selected villages of Vhembe District
… identified. The most common signs included the Milky Way Galaxy of stars, musical sounds of birds and frogs, moon shapes, cumulus and cumulonimbus cloud types. A close relationship between conservation of V. subterranea and adaptation strategies was said to exist. It was evident that most …
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Interstellar Gas Clouds and Gen. Ed. Astronomy Students: Who Are They? How Do They Behave?
… sample of star-forming regions in the Milky Way that likely span a wide range of evolutionary states. We study in detail the G111 Infrared Dark Cloud northwest of NGC 7538 with the K-band Focal Plane Array. We map NH₃ (1,1) and (2,2), H₂O maser, and CCS emission simultaneously with the …
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General-relativistic magnetohydrodynamics simulations of black hole accretion disks: dynamics and radiative properties
… the supermassive black hole at the center of our Milky Way galaxy, Sagittarius A* (Sgr A*). Owing to its proximity, rich observational data of Sgr A* is available to compare with the simulation results. We focus mainly on four topics. First, we analyse numerical convergence of 3D GRMHD global disk …
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Extragalactic Novae and Their Progenitors
… envelope increase until a thermonuclear runaway occurs. This causes a sudden increase in brightness (the outburst), which ranks among the most luminous stellar astrophysical phenomena.Following the outburst, some novae form detectable dust in the ejecta. Observationally, there is a …
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Search for Ultra-faint Milky Way Satellites
… satellite” problem: the distribution of observed Milky Way satellite galaxies appears to form a thin polar plane, which is largely inconsistent with the prediction of the standard cosmological model, i.e. an isotropic distribution of dark matter sub-halos. This problem was often seen as a …
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Search for Ultra-faint Milky Way Satellites
… satellite” problem: the distribution of observed Milky Way satellite galaxies appears to form a thin polar plane, which is largely inconsistent with the prediction of the standard cosmological model, i.e. an isotropic distribution of dark matter sub-halos. This problem was often seen as a …