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 22 for “"Stars, Interstellar Medium and the Galaxy"”.
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Processing of Simulated and Experimental Images of Closely Spaced Binary Stars Using Speckle Interferometry
<p>Theory and methods of processing speckle interferometry data from close visual binary stars are presented and implemented. The effects of the optical systems used for observing close visual binary stars are explained and simulated from both the geometrical and physical optical viewpoints. The …
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A Feasibility Study for Using the ERAU Échelle Spectrograph to Improve Orbital Parameters of Spectroscopic Binary Systems
<p>Binary stars are critical for establishing knowledge of stellar masses and refining the mass-luminosity relationship when used in conjunction with precise parallax measurements. However, many spectroscopic binaries have poorly defined orbital parameters as they have not been revisited with newer …
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Rotation Period Distributions and Light Curve Morphologies of Low Mass Stars and Young Associations
<p>This dissertation is centered around the rotation periods of low-mass stars and association of young stars. Rotation periods are a link to the age of the star, as they lose angular momentum over time. To understand how this angular momentum evolves requires understanding the rotation period …
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Star Formation History of the Milky Way Galaxy Disk Using a Hierarchical Model
<p>Whenever we see any celestial object, the first thing that comes to our mind is how old that object must be? It is 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 …
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Illustris-TNG Simulated Central Black Mass(MBH) and Galaxy Properties Correlations with a Machine Learning Approach
<p>Observationaly it is well established that the masses of central black holes are tightly correlated with galaxy properties, most notably the bulge’s velocity dispersion. Cosmolog- ical hydrodynamical simulations can capture most of these correlations, but it is yet not understood why this …
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A Rotating Aperture Mask for Small Telescopes
<p>Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small …
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Topics in the Detection of Gravitational Waves from Compact Binary Inspirals
… - such as binary black holes, binary neutron stars and neutron star-black hole binaries - are among the most promising sources of gravitational waves observable by ground-based interferometric detectors. Despite numerous sophisticated engineering techniques, the gravitational wave signals will …
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Neutron Star Electromagnetic Field Structure
<p>This dissertation investigates the neutron star magnetic field from generation to radiation production. We have investigated the spontaneous magnetization process to explain the magnetic field generation. This magnetization is then applied to determine the electromagnetic field structure of the …
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Feasibility of Circular Orbits for Proximity Operations in Strongly Perturbed Environments around Uniformly Rotating Asteroids
<p>Asteroids have been mapped and observed since 1801 when an Italian astronomer Guiseppe Piazzi discovered Ceres (Serio, Manara, & Sicoli, 2002). Since then, asteroids have been growing in popularity throughout the scientific community because they are thought to hold the information we need to …
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Stacking the Gamma-ray Sky to Search for Faint Astrophysical Populations
… from stellar flares to pulsating neutron stars, and 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 …
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A Photometric Study of the Eclipsing Binary V574 Lyrae
<p>Variable stars provide unparalleled insight into stellar evolution and eclipsing binary variables are particularly excellent laboratories for determining stellar physical parameters and behavior. These parameters, when taken with those of other stars, can be used to evaluate current theories on …
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The Mass-Pitch Angle Relation for Three High Redshift Active Galaxies Selected from the GOODS Field
<p>As we continue to investigate and ponder the heavens, we have come to realize the presence of highly energetic gravitational wells at the center of all galaxies. These supermassive black holes at a galaxies nucleus formed in the company of the other features making up the galaxy, particularly …
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Polarized Bow Shock Nebulae Reveal Features of the Winds and Environments of Massive Stars
<p>Massive stars strongly affect their surroundings through their energetic stellar winds during their lifetime and through their energetic deaths as supernovae. When a stellar wind interacts with the local interstellar medium (ISM), if the relative velocity between wind and ISM is supersonic, then …
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Identifying and Analyzing Multi-Star Systems Among TESS Planetary Candidates Using Gaia
… astrophysics where much is still unknown. It is therefore important to analyze trends among their parameters to learn more about these systems. More complexity is added to these systems with the presence of additional stellar companions. To study these complex systems, one can employ programming …
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Quartic Force Fields for Electronically Excited States of Interstellar Molecules
<p>Theoretical chemistry has advanced to the point where spectroscopic data can be produced that is directly comparable to high-accuracy experimental results. Quartic force field (QFFs) methods are one of the most efficient means of generating this data and have even shown spectroscopic accuracy …
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Classification of Variable Stars using Convolutional Neural Network
… Convolutional Neural Networks (CNNs), for the process of classifying and identifying variable stars through the analysis of unprocessed light curves from Transiting Exoplanet Survey Satellite (TESS). As astronomical data is becoming increasingly complex, and as advanced missions deploy …
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Celestial Paleontology: The Legacy of Dying Stars
<p>In their death throes, stars dole out their atmospheric material to the interstellar medium in dramatic stellar winds and spectacular explosions. The details of this profound metamorphosis, from star to remnant, play a key role in the next generation of star formation as well as the energetic …
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Exploring the Surface Liquid and Lake Regions of Titan with Laboratory Experimentation and Cassini Spacecraft Data
<p>The surface liquids and lake regions of Titan are studied utilizing three unique techniques, the results of which are reported in this dissertation. The development of a facility to simulate the surface conditions of Titan, and to conduct experiments on samples within that facility, brings an …
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A Spectrum of Light: Speculative Poetry of Celestial Bodies and Astrophysics
… on celestial objects within our solar system and larger bodies outside of our solar system, some of which are only theorized to exist. The author finishes the collection with introspective works, laying bare vulnerabilities and insecurities.</p>
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Development and Testing of a New Method for Velocity-Selecting White Dwarfs from Gaia by Galactic Population
<p>The detailed processes by which spiral galaxies form remains an open question in modern cosmology. Observations of the current configuration of spiral galaxies including the Milky Way reveal thin and thick disk and halo populations which must all be accounted for in formation theories and likely …
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