Physical Sciences and Mathematics Commons^™

Search For High-Energy Gamma Rays In The Northern Fermi Bubble Region With The Hawc Observatory, Hugo Alberto Ayala Solares

Dissertations, Master's Theses and Master's Reports

Gamma-ray astronomy is the study of very energetic photons, from E = m_ec² = 0.5x10⁶ eV to > 10²⁰eV. Due to the large span of the energy range, the field focuses on non-thermal processes that include the acceleration and propagation of relativistic particles, which can be found in extreme environments such as pulsars, supernova remnants, molecular clouds, black holes, etc.

The High Altitude Water Cherenkov (HAWC) observatory is an instrument designed for the study of gamma rays in the energy range of 100 GeV to 100 TeV. Using data from the HAWC observatory, a study …

Two Topics In Astrophysics: Exoplanetary Gravitational Microlensing And Radio Interferometry, Eleanor Sara Turrell

Senior Projects Spring 2017

Senior Project submitted to The Division of Science, Mathematics and Computing of Bard College.

Flickering Analysis Of Ch Cygni Using Kepler Data, Thomas Holden Dingus

Undergraduate Honors Theses

Utilizing data from the Kepler Mission, we analyze a flickering phenomenon in the symbiotic variable star CH Cygni. We perform a spline interpolation of an averaged lightcurve and subtract the spline to acquire residual data. This allows us to analyze the deviations that are not caused by the Red Giant’s semi-regular periodic variations. We then histogram the residuals and perform moment calculations for variance, skewness, and kurtosis for the purpose of determining the nature of the flickering. Our analysis has shown that we see a much smaller scale flickering than observed in the previous literature. Our flickering scale is on …

Gravitational Wave Astrophysics: Instrumentation, Detector Characterization, And A Search For Gravitational Signals From Gamma-Ray Bursts, Daniel Hoak

Doctoral Dissertations

In the coming years, the second generation of interferometric gravitational wave detectors are widely expected to observe the gravitational radiation emitted by compact, energetic events in the nearby universe. The field of gravitational wave astrophysics has grown into a large international endeavor with a global network of kilometer-scale observatories. The work presented in this thesis spans the field, from optical metrology, to instrument commissioning, to detector characterization and data analysis. The principal results are a method for the precise characterization of optical cavities, the commissioning of the advanced LIGO Output Mode Cleaner at the Hanford observatory, and a search for …

On The Spin Evolution Of Isolated Pulsars, Oliver Quinn Hamil

Doctoral Dissertations

Neutron stars are the remnants of supernova explosions, and harbor the densest matter found in the universe. Because of their extreme physical characteristics, neutron stars make superb laboratories from which to study the nature of matter under conditions of extreme density that are not reproducible on Earth. The understanding of QCD matter is of fundamental importance to modern physics, and neutron stars provide a means of probing into the cold, dense region of the QCD phase diagram.

Isolated pulsars are rotating neutron stars that emit beams of electromagnetic radiation into space which appear like lighthouses to observers on Earth. Observations …

The Effects Of Realistic Nuclear Kinetics, Dimensionality, And Resolution On Detonations In Low-Density Type Ia Supernovae Environments, Thomas L. Papatheodore

Doctoral Dissertations

Type Ia supernovae are most likely thermonuclear explosions of carbon/oxygen white dwarves in binary stellar systems. These events contribute to the chemical and dynamical evolution of their host galaxies and are essential to our understanding of the evolution of our universe through their use as cosmological distance indicators. Nearly all of the currently favored explosion scenarios for these supernovae involve detonations. However, modeling astrophysical detonations can be complicated by numerical effects related to grid resolution. In addition, the fidelity of the reaction network chosen to evolve the nuclear burning can alter the time and length scales over which the burning …

Infall As A Function Of Position And Molecular Tracer In Dense Cores., Jared Alan Keown

College of Arts & Sciences Senior Honors Theses

The standard model of prestellar core collapse suggests that this process works from the inside and moves outwards, with the fastest motions at the center. The relative abundances of many molecules also vary within cores, with certain molecules found only in specific regions characterized by narrow ranges of temperature and density. These characteristics lead to the hypothesis that the observed infall speeds in starless cores depend on both the position of the observations and the molecular tracer chosen. By measuring line emission at multiple positions across a core using an array of tracer molecules, one can determine whether these theoretical …

Graphic Representation Of Exotic Nuclear Shapes In The Pasta Phase Of Matter In Neutron Stars, Mark A. Kaltenborn

Chancellor’s Honors Program Projects

No abstract provided.

Three Dimensional Equation Of State For Core-Collapse Supernova Matter, Helena Sofia De Castro Felga Ramos Pais

Doctoral Dissertations

The core-collapse supernova (CCSN) phenomenon, one of the most explosive events in the Universe, presents a challenge to theoretical astrophysics. Stellar matter in supernovae, experiencing most extreme pressure and temperature, undergoes transformations that cannot be simulated in terrestrial laboratories. Construction of astrophysical models is the only way towards comprehension of CCSN. The key microscopic input into CCSN models is the Equation of State (EoS), connecting the pressure of stellar matter to the energy density and temperature, dependent upon its composition. Of the large variety of forms of CCSN matter, we focus on the transitional region between homogeneous and inhomogeneous phases. …

Molecular Processes In Astrophysics: Calculations Of H + H2 Excitation, De-Excitation, And Cooling, Matthew Kelley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The implications of H+H2 cooling in astrophysics is important to several applications. One of the most significant and pure applications is its role in cooling in the early universe. Other applications would include molecular dynamics in nebulae and their collapse into stars and astrophysical shocks. Shortly after the big bang, the universe was a hot primordial gas of photons, electrons, and nuclei among other ingredients. By far the most dominant nuclei in the early universe was hydrogen. In fact, in the early universe the matter density was 90 percent hydrogen and only 10 percent helium with small amounts of lithium …

First Mover: Otto Struve And The Use Of Scientific Capital In Astrophysics, 1921–1950, Erik Paul Norquest

Theses and Dissertations - UTB/UTPA

Otto Struve (1897-1963) came to the United States in 1921 and became one of the dominant personalities in the field of astrophysics. Struve’s career made him, in the words of sociologist Pierre Bourdieu, a “first mover” in a scientific field that was firmly engaged in the process of what Thomas Kuhn called “normal science.” Struve pulled astrophysics further away from its empirical roots in categorization and made it more like physics in its unification of theory and observation. The primary way that he accomplished this was through his administration of Yerkes and McDonald observatories, where he brought in theorists to …

Internal Transitions In Nuclei And Applications To Astrophysics And Cosmochemistry, Joseph Johnson

All Dissertations

In this dissertation I analyze internal transitions in nuclei and their potential effects on s-process branching and on accelerated β-decay in cosmochemical samples. To accomplish my analysis, I have constructed a number of computational tools, which I have publicly released or make available through this thesis. I apply my analysis to the question of s-process branching at 186Re and study the implications for the osmium isotopes in mainstream presolar SiC grains. My essential conclusion is that the problem of the large neutron flux inferred from the SiC osmium isotopic abundances cannot be solved by branching through an out-of-equilibrium isomer of …