Other Astrophysics and Astronomy Commons^™

Black Holes, Disk Structures, And Cosmological Implications In E-Dimensional Space, Subhash Kak, Menas C. Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

We examine a modern view of the universe that builds on achieved successes of quantum mechanics, general relativity, and information theory, bringing them together in integrated approach that is founded on the realization that space itself is e-dimensional. The global and local implications of noninteger dimensionality are examined, and how it may have increased from the value of zero to its current value is investigated. We find surprising aspects that tie to structures in the universe, black holes, and the role of observations.

Multifrequency Scintillation In The Polar Caps, Tate Colby

Doctoral Dissertations and Master's Theses

In the ionosphere, plasma density structures with scales sizes ranging from a few centimeters to hundreds of kilometers are capable of modifying the phase and amplitude of a radio signal in a rapid random manner in a process called scintillation. The Coherent Electromagnetic Radio Tomography (CERTO) and the Canadian High Arctic Ionospheric Network (CHAIN) are two different networks of scintillation receivers, each with a station in Resolute Bay, Canada. CERTO measures amplitude and phase signals in VHF and UHF while CHAIN measures amplitude and phase signals in the L-band. Through these measurements we can calculate the scintillation indexes, S_4 and …

Photoionization Energetics And Dissociation Pathways Of Hydroperoxyethyl Formate Produced In The Reaction Of Ch3Choo + Formic Acid, Vincent J. Esposito, Trent A. Mchenry, Marsha I. Lester

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The bimolecular reaction of Criegee intermediates, zwitterionic carbonyl oxide species produced in alkene ozonolysis, with organic acids leads to formation of functional hydroperoxides implicated in the generation of atmospheric aerosols. This theoretical study using high-level explicitly correlated coupled-cluster theory examines the low energy conformers of hydroperoxyethyl formate [HOOCH(CH₃)OCHO, HPEF] formed in the bimolecular reaction of CH₃CHOO, a simple alkyl-substituted Criegee intermediate, with formic acid, and the detection of HPEF via photoionization. The vertical and adiabatic ionization energies of HPEF are computed, along with the pathways for dissociative ionization that produce HO₂ or OCHO fragments with …

A New Wave Of “Space Nationalism” In The United States: Why Are Evangelicals Good With It?, Andrea Molle

Political Science Faculty Articles and Research

Despite evidence that shows how the support for space programs correlates with liberal political views and a lower level of religiosity, recent data suggest that more conservative positions may have an even more substantial effect under the appropriate conditions. Using the available data from Pew's American Trends Panel, we seek to clarify this interactional effect of political and religious preferences on the level of interest in the space programs and commitment to space politics support among Evangelicals as it changed during Trump's presidency. Our research hypothesizes that during this time, the simultaneous presence of nationalist views in both accounts of …

Spectroscopic Properties Of The Astrochemical Molecules [Al, O, Si]X (X = 0, +1), Jacqueline M. Friskey, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aluminum and silicon are present in large quantities in the interstellar medium, making the triatomic species consisting of both elements intriguing with regard to the foundations of astrochemistry. Spectroscopic parameters have been calculated via high-level ab initio methods to assist with laboratory and observational detection of [Al, O, Si]^x(x = 0,+1). All [Al, O, Si]M^x(x = 0,+1) isomers exist in the linear geometry, with linear AlOSi (X ²Π) and linear AlOSi⁺ (X¹Δ) being the most stable neutral and cationic species, respectively. Formation of the neutral species most likely occurs via reaction of …

A Wind Environment And Lorentz Factors Of Tens Explain Gamma-Ray Bursts X-Ray Plateau, Hüsne Dereli-Bégué, Asaf Pe’Er, Felix Ryde, Samantha R. Oates, Bing Zhang, Maria G. Dainotti

Physics & Astronomy Faculty Research

Gamma-ray bursts (GRBs) are known to have the most relativistic jets, with initial Lorentz factors in the order of a few hundreds. Many GRBs display an early X-ray light-curve plateau, which was not theoretically expected and therefore puzzled the community for many years. Here, we show that this observed signal is naturally obtained within the classical GRB fireball model, provided that the initial Lorentz factor is rather a few tens, and the expansion occurs into a medium-low density wind. The range of Lorentz factors in GRB jets is thus much wider than previously thought and bridges an observational gap between …

Dirac Dark Matter, Neutrino Masses, And Dark Baryogenesis, Diego Restrepo, Andrès Rivera, Walter Tangarife

Physics: Faculty Publications and Other Works

We present a gauged baryon number model as an example of models where all new fermions required to cancel out the anomalies help to solve phenomenological problems of the standard model (SM). Dark fermion doublets, along with the isosinglet charged fermions, in conjunction with a set of SM-singlet fermions, participate in the generation of small neutrino masses through the Dirac-dark Zee mechanism. The other SM-singlets explain the dark matter in the Universe, while their coupling to an inert singlet scalar is the source of the CP violation. In the presence of a strong first-order electroweak phase transition, this “dark” CP …

Using Neural Network To Search For Isolated Hα Clouds In The Virgo Cluster, Audra Carver

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

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 …

Stacking The Gamma-Ray Sky To Search For Faint Astrophysical Populations, Yuzhe Song

Dissertations, Theses, and Capstone Projects

Gamma-ray emission can be generated from a wide variety of high-energy astrophysical phenomena, 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 board. The latest Fermi source catalog contains over 6000 sources. Yet, a lot of sources that are expected to emit γ-rays are not detected, and only small percentages of some populations are detected. For example, solar flares are detected in …

Mining The Data Cubes In Sub-Mm And Optical Astronomy, Nathanael Pichette

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

The Pursuit For Gamma-Ray Emitting Pulsar Wind Nebulae With The Fermi-Large Area Telescope, Jordan Eagle

All Dissertations

Pulsar wind nebulae are highly magnetized particle winds, descending from core collapse supernovae (CC SNe), and each powered by an energetic, rapidly rotating neutron star. There are at least 125 Galactic pulsar wind nebulae (PWNe) that have been discovered from radio wavelengths to TeV gamma-rays, the majority of which were first identified in radio or X-ray surveys. An increasing number of PWNe are being identified in the TeV band by ground-based air Cherenkov Telescopes such as HESS, MAGIC, and VERITAS such that they constitute the dominant source class of Galactic TeV emitters. High-energy sources like PWNe may be responsible for …

Co Molecular Spectroscopy And Spectro-Astrometry Of Protoplanetary Disks, Stanley Jensen

All Dissertations

Until relatively recently, the only known planets were those in our own solar system (Mayor & Queloz, 1995). However modern instruments and techniques have revealed that planets are ubiquitous around main sequence stars over the last three decades. From this we have obtained a multitude of insights into planetary populations. For instance, while the terrestrial and gas giant planet types are both well accounted for in extra-solar systems, the arrangement of our own system with inner terrestrial planets and outer gas giants is not clearly the typical organization (van der Marel & Mulders, 2021). In fact we see that in …

The Photoionization Dynamics, Electronic Spectroscopy, And Excited State Photochemistry Of Alco And Aloc, Vincent J. Esposito, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The high cosmic abundance of carbon monoxide (CO) and the ubiquitous nature of aluminum-coated dust grains sets the stage for the production of weakly bound triatomic molecules AlCO (X ²Π) and AlOC (X ²Π) in circumstellar envelopes of evolved stars. Following desorption of cold AlCO and AlOC from the dust grain surface, incoming stellar radiation in the 2–9 eV wavelength range (visible to vacuum ultraviolet) will drive various photochemical processes. Ionization to the singlet cation state will cause an immediate Al–X (X = C, O) bond dissociation to form Al⁺ (¹S) and CO (X ^{1 …}

A Comparison Of Exotic And Pyraf In Analyzing Exoplanet Transits, Kailei A. Gallup

Physics

In this paper we discuss the data analysis processes using PyRaf, a Python-based version of IRAF, which is one of the most commonly used coding softwares in the astronomy community, as well as the analysis process using EXOTIC. Additionally, we will compare the outcomes from each process to determine if either has significant benefits over the other.

Analysis Of Comet Rotation Through Modeling Of Features In The Coma, Ien Harris

Theses and Dissertations

An integral field unit fiber array spectrograph was used to observe the emission spectra of radical species (C2, C3, CH, CN, and NH2) in multiple comets. The resultant azimuthal and radial division maps produced from the reduced data provide a unique method of analyzing features with these radicals in the comae, as well as how they behave over time. A Monte Carlo model was developed in order to simulate the behavior of particles from the outer nucleus and coma of each comet depending on various parameters including rotational period, outflow velocity, and active area location. The results from the model …

Aloso: Spectroscopy And Structure Of A New Group Of Astrochemical Molecules, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

No abstract provided.

Optimization Of Orbital Trajectories Using Neuroevolution Of Augmenting Topologies, Nathan Wetherell

University Scholar Projects

This project aims to determine the feasibility of using NeuroEvolution of Augmenting Topologies (NEAT), an advanced neural network evolution scheme, to optimize orbital transfer trajectories. More specifically, this project compares a genetically evolved neural network to a standard Hohmann transfer between Earth and Mars. To test these two methods, an N-body simulation environment was created to accurately determine the result of gravitational interactions on a theoretical spacecraft when combined with planned engine burns. Once created, this simulation environment was used to train the neural networks created using the NEAT Python module. A genetic algorithm was used to modify the topology …

Monitoring The M-Dwarf Host Stars Of Tess Exoplanet Candidates: Stellar Flares And Habitability, Ashley Lieber

Physics Undergraduate Honors Theses

In the search for life beyond our solar system, the study of M-dwarfs has become increasingly important due to their unique characteristics including their small size, flaring capabilities, and long lifespans. Their small size allows for exoplanet detection due to observable gravitational interactions, and the stellar flares could potentially trigger prebiotic life on exoplanets in the system. Lastly, their long lifespans may provide the conditions necessary to foster prebiotic life and the development of more complex organisms over time. Flare rate is a critical factor in determining the habitability of the exoplanet due to its potential to damage or incubate …

Exploring The Glow Of The Universe In Gamma-Rays And Hunting Distant Agn, Changam Meenakshi Rajagopal

All Dissertations

The entirety of the γ-ray radiation permeating our Universe is encoded in the extragalactic γ-ray background. This is a superposition of resolved sources, mostly powerful relativistic jets powered by supermassive black holes, i.e., blazars, and an unresolved isotropic component, aka, the diffuse isotropic gamma-ray background (IGRB). Studying the IGRB can help unveil its composition, as well as unearth multi-messenger relationships between the intensities of PeV neutrinos, ultra high energy cosmic rays (> 1018 eV), and sub-TeV γ-rays. The comparable energy budgets of these three phenomena (neutrinos, UHECR, and γ-rays) indicates a physical connection or a common source amongst them. On …

Are Long-Period Exoplants Around Cool Stars More Common Than We Thought?, Emily Jane Safron

LSU Doctoral Dissertations

The Kepler mission has been the catalyst for discovery of nearly 5,000 confirmed and candidate exoplanets. The majority of these candidates orbit Sun-like stars, and have orbital periods comparable to or shorter than that of the Earth, due to the selection bias inherent in the transit method and the limitations of automated transit search algorithms. We aim to develop a richer understanding of the population of exoplanets around the lowest-mass stars, the M spectral type. We are particularly interested in exoplanets with long orbital periods, which are difficult or impossible to find using standard transit search algorithms. In our study, …

Spectroscopic Properties Relevant To Astronomical And Laboratory Detection Of Mch And Mch+ (M = Al, Mg), Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

New spectroscopic parameters have been calculated to aid in the laboratory and observational detection of AlCH, AlCH⁺, MgCH, MgCH⁺, and their deuterated analogs. All species exist in linear geometry except for AlCH+, which exhibits a bent structure. Rotational frequencies have been calculated and the transition with maximum intensity is discussed for three temperature regions present in space: 100 K for a central circumstellar envelope (CSE), 30 K for an outer CSE, and 3 K indicative of the interstellar medium. Pertinent frequencies range from 25 to 250 GHz, depending on the species. At 30 K, the most …

The Meaning Of Dark, Light And Shadows: Inferences In Art, Materiality And Cultural Practices, Frank Prendergast

Book/Book Chapter

Our visual awareness relies on light acting on the eye to perceive materiality and colour. Medieval thought wrestled to articulate and comprehend its nature. The notebooks of Leonardo Da Vinci, for example, included his descriptions to define light and make comparisons so as to differentiate between light and shadow. His focus was on the illumination of surfaces from the perspective of a painter, seeing shadows as ‘the diminution of light by the intervention of an opaque body’ and ‘the counterpart of luminous rays’. In his mind, a shadow ‘stood between light and darkness’, with darkness being ‘the absence of light’. …

Investigating Signs Of Orbital Decay In The Tres-1 Exoplanetary System, Amanda F. Wester

Honors Theses and Capstones

Transit observations of exoplanetary systems can be used to investigate orbital decay. TrES-1b is an exoplanet hypothesized to be experiencing orbital decay due to observed transit timing variations (TTVs) [12]. Numerous transits must be observed to establish a long term pattern to conclusively determine if the planet’s orbit is decaying. Measurements were made using the UNH Observatory where 2 transits were observed of the TrES-1b transiting system on February 27, 2022 and March 5, 2022. A CCD camera was used to image the transit and capture calibration images. The software AstroImageJ (AIJ) was used to calibrate the images and perform …

Searching For Anomalous Extensive Air Showers Using The Pierre Auger Observatory Fluorescence Detector, Andrew Puyleart

Dissertations, Master's Theses and Master's Reports

Anomalous extensive air showers have yet to be detected by cosmic ray observatories. Fluorescence detectors provide a way to view the air showers created by cosmic rays with primary energies reaching up to hundreds of EeV . The resulting air showers produced by these highly energetic collisions can contain features that deviate from average air showers. Detection of these anomalous events may provide information into unknown regions of particle physics, and place constraints on cross-sectional interaction lengths of protons. In this dissertation, I propose measurements of extensive air shower profiles that are used in a machine learning pipeline to distinguish …

Preliminary Studies Of Background Rejection Capabilities For The Southern Wide−Field Gamma−Ray Observatory, Sonali Mohan

Dissertations, Master's Theses and Master's Reports

The Southern Wide-field Gamma-ray Observatory (SWGO), is a next-generation
gamma-ray observatory to be constructed in the Southern Hemisphere that will com-
plement current and future instruments by providing a wide-field coverage of a large
portion of the southern sky and a better sensitivity to the 100 GeVs to few PeVs
photon band to understand extreme astrophysical phenomena throughout the uni-
verse. Air shower events initiated by gamma rays will be recorded by the detector
and reconstructed to extract shower properties. The challenge for air-shower arrays
in the observation of gamma-ray sources is the large background of hadronic cos-
mic rays. …

A Combined Spectral And Energy Morphology Analysis Of Gamma Ray Source Hawc J2031+415 In The Cygnus Constellation, Ian Herzog

Dissertations, Master's Theses and Master's Reports

HAWC J2031+415 is a probable pulsar wind nebula (PWN) located in the Cygnus Cocoon region near a complex OB star cluster. First observed by the High-Energy-Gamma-Ray Astronomy (HEGRA) observatory in the TeV energy regime, the source had no apparent counterpart in lower energy ranges. Previous work using 1343 days of data from the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory has determined that three sources are present in the Region of Interest (ROI): HAWC J2031+415, HAWC J2030+409 (also known as the Cocoon), and 3HWC J2020+403 (associated with the Gamma Cygni supernova remnant) \cite{Ian_01, Binita_01}.

In this work, I use the newest …

Toward Deep Learning Emulators For Modeling The Large-Scale Structure Of The Universe, Neerav Kaushal

Dissertations, Master's Theses and Master's Reports

Multi-billion dollar cosmological surveys are being conducted almost every decade in today’s era of precision cosmology. These surveys scan vast swaths of sky and generate tons of observational data. In order to extract meaningful information from this data and test these observations against theory, rigorous theoretical predictions are needed. In the absence of an analytic method, cosmological simulations become the most widely used tool to provide these predictions in order to test against the observations. They can be used to study covariance matrices, generate mock galaxy catalogs and provide ready-to-use snapshots for detailed redshift analyses. But cosmological simulations of matter …

Impact Of Radio Frequency Interference And Real-Time Spectral Kurtosis Mitigation, Evan T. Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

We catalog the ubiquity of Radio Frequency Interference (RFI) plaguing every modern radio telescope and investigate several ways to mitigate it in order to create better science-ready data products for astronomers. There are a myriad of possible RFI sources, including satellite uplinks and downlinks, cellular communications, air traffic radar, and natural sources such as lightning. Real-time RFI mitigation strategies must take these RFI characteristics into account, as the interfering signals can look significantly different at very high time and frequency resolutions.

We examine Spectral Kurtosis (SK) as a real-time statistical RFI detection method, and compare its flagging efficacy against simulated …

Deep Learning Detection In The Visible And Radio Spectrums, Greg Clancy Murray

Graduate Theses, Dissertations, and Problem Reports (ETD)

Deep learning models with convolutional neural networks are being used to solve some of the most difficult problems in computing today. Complicating factors to the use and development of deep learning models include lack of availability of large volumes of data, lack of problem specific samples, and the lack variations in the specific samples available. The costs to collect this data and to compute the models for the task of detection remains a inhibitory condition for all but the most well funded organizations. This thesis seeks to approach deep learning from a cost reduction and hybrid perspective — incorporating techniques …