Cosmology, Relativity, and Gravity Commons^™

Stellar Atmosphere Models For Select Veritas Stellar Intensity Interferometry Targets, Jackson Ladd Sackrider, Jason P. Aufdenberg, Katelyn Sonnen

Beyond: Undergraduate Research Journal

Since 2020 the Very Energetic Radiation Imaging Telescope Array System (VERITAS) has observed 48 stellar targets using the technique of Stellar Intensity Interferometry (SII). Angular diameter measurements by VERITAS SII (VSII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars …

Weak Gravitational Lensing Analysis In Two Superclusters Of Galaxies, Sarah B. Rice

Electronic Theses and Dissertations

Observations of the Universe on very large scales have shown it to be filled with galaxy clusters and superclusters connected by walls and filaments of galaxies, with vast areas mostly devoid of luminous matter separating them. It is widely accepted that the amount of luminous matter does not provide the mass needed to hold galaxies and galaxy clusters together, and the nature of the missing "dark matter" is one of the most prominent astrophysical mysteries today. Since dark matter interacts with luminous matter gravitationally, it stands to reason that dark matter might organize itself in a similar manner to luminous …

Detectability Of Wormholes Through Various Methods, Jonathan W. Keathley

PANDION: The Osprey Journal of Research and Ideas

There are three methods that can possibly detect wormholes: Negative Temperature, Hawking/ Phantom Radiation, and Kα iron emission lines. This paper discusses whether or not any of these three methods are useful ways to detect wormholes with today’s technology and if so, which one is the best and which is the worst. As it turns out, all of these methods have their flaws and impracticalities. After looking through all the evidence and comparing it to what capabilities we have currently, there is clearly a best and worst method. The best method to detect possible wormhole candidates is through the detection …

Astrophysics, Cosmology And Particle Phenomenology At The Energy Frontier, Jorge Fernandez Soriano

Dissertations, Theses, and Capstone Projects

This dissertation consists of two parts, treating significantly separated fields. Each part consists on several chapters, each treating a somewhat isolated topic from the rest. In each chapter, I present some of the work developed during my passage through the graduate program, which has mostly been published elsewhere.

Part I – Cosmic Rays and Particle Physics

• Chapter 1: In this chapter we present an introduction to the topic of cosmic ray physics, with an special focus on the so-called ultra high energy cosmic rays: their potential origins, effects during their propagation between their sources and Earth, the different techniques used …

Understanding Martian Salts And Their Implications For Liquid Water, Rachel Slank

Graduate Theses and Dissertations

Water is one of the key components for life as we know it. The existence of salts on Mars has been a large contributing factor to the possibility of habitability, due to their ability to allow liquid water to remain stable at colder temperatures. Salts, including perchlorates, chlorates, and chlorides, have been detected by multiple landers, rovers, and orbiters, and are now believed to be ubiquitous on Mars. One of the pathways to liquid brine solutions is through deliquescence. Deliquescence is the transition from a solid salt crystal into an aqueous solution when exposed to a humid atmosphere. This research …

Fermion-Induced Electroweak Symmetry Non-Restoration Via Temperature-Dependent Masses, Yu Hang Ng

Theses, Dissertations, and Student Research: Department of Physics and Astronomy

Standard Model (SM) and many extensions of SM predict that the electroweak (EW) symmetry was restored in the early universe when the temperature was around 160 GeV. However, recent studies showed that the interactions between some new scalars and SU(2)_L Higgs doublet(s) can cause the EW symmetry to remain broken at temperatures well above the EW scale in certain renormalizable extensions of SM. In this study, we found that new fermions from renormalizable models can also induce this EW symmetry non-restoration effect, provided that they have the appropriate temperature-dependent masses. These masses can arise naturally from the interactions between the …

The Cosmic History Of X-Ray Binary Evolution, Woodrow Gilbertson

Graduate Theses and Dissertations

The Chandra Deep Fields provide an extraordinary window into the high-energy history of the cosmos. Observations of non-active galaxies within the deep fields can be leveraged to extract information about the formation and evolution of X-ray binaries (XRBs). Previous studies have suggested that the evolution of XRB luminosity can be expressed a function of physical parameters such as star formation rate, stellar mass, stellar age, and metallicity. The goal of this work is to develop and implement a complete physical parameterization for the luminosity of XRB populations, which can be utilized for a variety of further studies.

Chapter 1 provides …

Surpassing The Standard Quantum Limit Using An Optical Spring, Torrey Cullen

LSU Doctoral Dissertations

In 1916, Albert Einstein predicted the existence of gravitational waves based on his new theory of general relativity. He predicted an accelerating mass with a non-zero quadrupole moment would emit energy in the form of gravitational waves. Often referred to as ripples in space-time, gravitational waves are extremely small by the time reach Earth, potentially having traveled hundreds of megaparsecs. It is common for these ripples in space-time to stretch and squeeze matter 1000 times smaller than the width of a proton.
Laser interferometer observatories were first built in the 1990s in the US and Europe, and as sensitivity improvements …

Challenging Predictions Of Inflationary Models With Cmb Data, Richik Bhattacharya, Atanu Debnath, Esha Sajjanhar, Shravani Sardeshpande, Pablo Tenorio Hernández, José Ricardo Torres Heredia

2022 REYES Proceedings

Cosmic inflation offers the best known explanations for many of the observed features of the Universe, such as its flatness. An imprint of the qualities of this mechanism is left in the cosmic microwave background (CMB), which can be instrumental to confirm inflation. Unfortunately, there is a plethora of inflationary models, which are a priori in the same footing. It is conceivable that contrasting the predictions of the various models with the measured values of the parameters of CMB data and other cosmological observables shall allow one to single out the successful theory of inflation. In this work we provide …

Calibration Of The Lux-Zeplin Dual-Phase Xenon Time Projection Chamber With Internally Injected Radioisotopes, Christopher D. Nedlik

Doctoral Dissertations

Self-shielding in ton-scale liquid xenon (LXe) detectors presents a unique challenge for calibrating detector response to interactions in the detector's innermost volume. Calibration radioisotopes must be injected directly into the LXe to reach the central volume, where they must either decay away with a short half life or be purified out. We present an overview of, and results from, the prototype source injection system (SIS) developed at the University of Massachusetts Amherst for the LUX-ZEPLIN experiment (LZ). The SIS is designed to refine techniques for the injection and removal of precise activities of various calibration radioisotopes that are useful in …

From Equal-Mass To Extreme-Mass-Ratio Binary Inspirals: Simulation Tools For Next Generation Gravitational Wave Detectors, Samuel Douglas Cupp

LSU Doctoral Dissertations

Current numerical codes can successfully evolve similar-mass binary black holes systems, and these numerical waveforms contributed to the success of the LIGO Collaboration's detection of gravitational waves. LIGO requires high resolution numerical waveforms for detection and parameter estimation of the source. Great effort was expended over several decades to produce the numerical methods used today. However, future detectors will require further improvements to numerical techniques to take full advantage of their detection capabilities. For example, the Laser Interferometer Space Antenna (LISA) will require higher resolution simulations of similar-mass-ratio systems than LIGO. LISA will also be able to detect extreme-mass-ratio inspiral …

Introduction To Classical Field Theory, Charles G. Torre

All Complete Monographs

This is an introduction to classical field theory. Topics treated include: Klein-Gordon field, electromagnetic field, scalar electrodynamics, Dirac field, Yang-Mills field, gravitational field, Noether theorems relating symmetries and conservation laws, spontaneous symmetry breaking, Lagrangian and Hamiltonian formalisms.

Utilizing Post-Newtonian Expansion To Determine Parameters Of Compact Binary Black Hole Mergers, Jarrod E. Rudis

Honors College

The process of determining parameters of black hole mergers requires complicated formulae like the Einstein Field Equations (EFEs) that can only be solved numerically with the help of supercomputers. This paper sought to explore an alternative method to prediction of parameters through the use of 1st order Post-Newtonian Expansion (PNE), which is a way of approximating solutions to the EFEs. Two binary- black hole mergers, GW170814 and GW170809 were analyzed with the use of 1st order PNE to obtain the chirp mass and radiated energy parameters. These parameters were then compared with the parameters obtained using numerical solutions to the …

Spin-Orbit Gravitational Locking - An Effective Potential Approach, Christopher Clouse, Andrea Ferroglia, Miguel C. N. Fiolhais

Publications and Research

The objective of this paper is to study the tidally locked 3:2 spin–orbit resonance of Mercury around the Sun. In order to achieve this goal, the effective potential energy that determines the spinning motion of an ellipsoidal planet around its axis is considered. By studying the rotational potential energy of an ellipsoidal planet orbiting a spherical star on an elliptic orbit with fixed eccentricity and semi-major axis, it is shown that the system presents an infinite number of metastable equilibrium configurations. These states correspond to local minima of the rotational potential energy averaged over an orbit, where the ratio between …

The World As We Know It: Maps And Atlases From Special Collections, Archives And Special Collections, Luke Meagher

Library Exhibits

Selections of maps and atlases from Sandor Teszler Library’s Special Collections are presented in this exhibit to show how, over time, cartographers have represented the world as we know it.

Venus Mountain Waves In The Upper Atmosphere Simulated By A Time-Invariant Linear Full-Wave Spectral Model, Michael P. Hickey, Richard L. Walterscheid, Thomas Navarro, Gerald Schubert

Publications

A 2-D spectral full-wave model is described that simulates the generation and propagation of mountain waves over idealized topography in Venus' atmosphere. Modeled temperature perturbations are compared with the Akatsuki observations. Lower atmosphere eddy diffusivity and stability play a major role in the upward propagation of gravity waves from their mountain sources. Two local times (LT) are considered. For LT = 11 h the waves are blocked by a critical level near 100 km altitude, while for LT = 16 h the waves propagate into the thermosphere. As a result of the small scale height in the Venus thermosphere, for …

A New Non-Inheriting Homogeneous Solution Of The Einstein-Maxwell Equations With Cosmological Term, Ian M. Anderson, Charles G. Torre

Publications

We find a new homogeneous solution to the Einstein-Maxwell equations with a cos- mological term. The spacetime manifold is R × S3. The spacetime metric admits a simply transitive isometry group G = R × SU(2) and is Petrov type I. The spacetime is geodesically complete and globally hyperbolic. The electromagnetic field is non- null and non-inheriting: it is only invariant with respect to the SU(2) subgroup and is time-dependent in a stationary reference frame.

A New Non-Inheriting Homogeneous Solution Of The Einstein-Maxwell Equations With Cosmological Term, Charles G. Torre

Research Vignettes

No abstract provided.

What's New In Differentialgeometry Release Dg2022, Ian M. Anderson, Charles G. Torre

Tutorials on... in 1 hour or less

This Maple worksheet demonstrates the salient new features and functionalities of the 2022 release of the DifferentialGeometry software package.

The Differentialgeometry Package, Ian M. Anderson, Charles G. Torre

Downloads

This is the entire DifferentialGeometry package, a zip file (DifferentialGeometry.zip) containing (1) a Maple Library file, DifferentialGeometryUSU.mla, (2) a Maple help file DifferentialGeometry.help, (3) a Maple Library file, DGApplicatons.mla. This is the latest version of the DifferentialGeometry software; it supersedes what is released with Maple.

Installation instructions