Physical Sciences and Mathematics Commons^™

Novel Machine Learning Methods For Quasar Variability And Strong Gravitational Lensing, Joshua Fagin

Dissertations, Theses, and Capstone Projects

Machine learning methods are well suited to handle the unprecedented data volume expected from upcoming wide-field surveys. The European Space Agency's Euclid telescope was launched in July 2023 and is expected to observe billions of galaxies at high resolution, including tens of thousands of strongly lensed galaxies. The Rubin Observatory Legacy Survey of Space and Time (LSST) will monitor tens of millions of quasars throughout its ten-year lifetime, thousands of which will be strongly lensed. This flood of data will enable measuring lens galaxy mass distributions and substructure, as well as probing quasar accretion disk structure and black hole properties …

Leveraging Stellar Chemistry For A Global View Into The Atmospheres Of Brown Dwarfs And Giant Exoplanets, Emily Calamari

Dissertations, Theses, and Capstone Projects

In the era of the James Webb Space Telescope (JWST), it is now possible to examine substellar mass atmospheres in unparalleled detail and precision. However, unraveling the complicated thermodynamics and chemistry in these atmospheres remains a challenge. Atmospheric retrievals are a leading data-driven technique capable of recovering an object’s fundamental parameters such as mass, radius, effective temperature, gravity, cloud structure and composition and chemical abundances. However, in directly imaged or isolated worlds, constraining and/or interpreting these fundamental parameters can be difficult, particularly as retrieval models try to parameterize the overall impact of clouds.

For my dissertation, I turned to main …

Investigating The Behavior Of Dwarf-Hosting Cosmic Filaments In Regions Of Average Density Within The Universe, Manuel E. Ramirez Hernandez

Dissertations, Theses, and Capstone Projects

The cosmic web is the large-scale structure of the universe, composed of elongated, overdense areas held together by gravity known as cosmic filaments. Within these filaments, dwarf galaxies are ubiquitous and make for excellent laboratories due to their small size. to determine the effects of cosmic web structures on dwarf galaxies. In this thesis, I laid the groundwork to investigate whether dwarf galaxy populations vary across different types of filaments. Filaments were extracted from the gas density field in the New Horizon simulation at $z=0$ using the topological feature finder DisPerSE. I determined the distances of galaxies to their nearest …

Effect Of Equation Of State On The Formation Of Binary Black Holes In Active Galactic Nucleus Disks, Theodore Edwards

Dissertations, Theses, and Capstone Projects

Active galactic nucleus disks have been proposed as a possibly dominant location of the mergers of binary black holes detected by gravitational wave observatories. The nonlinear interactions between stellar mass black holes and disk gas determine when binaries will form from single objects on nearby orbits. Prior work has used smoothed particle hydrodynamics models in an isothermal disk to study this problem. However, the local equation of state near the midplane of an optically thick accretion disk is adiabatic rather than isothermal, even if the radiative equilibrium temperature is azimuthally isothermal. Therefore, we investigate the use of an adiabatic equation …

How To Form A Gravitational-Wave Source: Quantifying Intermediate Evolutionary Stages In Isolated Binary Stellar Evolution, Ana Lam

Dissertations, Theses, and Capstone Projects

Gravitational-wave (GW) detections from double compact object (DCO) mergers provide crucial observational constraints for understanding massive stars across cosmic time. Coupled with these observations, binary population synthesis simulations become powerful tools for probing the formation, evolution, and ultimate fates of their progenitors---massive binary stars. However, complex evolutionary pathways, shaped by key intermediate stages such as mass transfer phases and supernovae, present a significant challenge to assess their impact. To address this, we develop a framework to quantify the influence of intermediate evolutionary stages on GW sources. By combining Sankey diagrams with survival factors, we systematically investigate how intermediate stages influence …

Satellite-Host Galaxy Co-Evolution With Next-Generation Regulator Models, Austen Gabrielpillai

Dissertations, Theses, and Capstone Projects

The evolution of satellites galaxies is an unsolved problem in galaxy formation. Recent observations such as the SAGA and ELVES surveys find tension in HI contents and star formation of satellites around their central host galaxies when compared to our own local environment, the Milky Way. These processes are potentially highly influenced by the host's circumgalactic medium (CGM), and to constrain these cases requires accurate and fast modeling of satellites-host interactions. In this work, we present our methodology for evolving z = 0 surviving satellites alongside their central galaxy in sapphire, a CGM regulator co-evolution model of galaxy formation. …

The Density Distribution Of The Material Around Betelgeuse, Iman Behbehani

Dissertations, Theses, and Capstone Projects

Betelgeuse is a red supergiant star visible in the constellation Orion. Its windy and highly convective surface results in a complicated mass loss pattern difficult to understand and replicate in simulations. The ejected mass can form a shell around the star we consider the circumstellar material (CSM). In this study, we use ALMA interferometric observations to find the structure of Betelgeuse's CSM, and connect to the mass loss mechanisms that could form it. We measure a bipolar circumstellar structure with a position angle of 42.3$\pm 7.0^\circ$. We observe asymmetries in the form of hot spots in the north east of …

Refining Orbits And Revealing Origins: A Study Of Giant Exoplanets Around Low-Mass Stars, Angeli Sandoval

Dissertations, Theses, and Capstone Projects

The study of gas giants around low-mass stars offers important insight into planet formation. Core accretion models predict that these planets should have a low likelihood of forming due to the limited disk masses of their host low-mass stars. However, NASA space missions such as Kepler and TESS have revealed an emerging population of Saturn- and Jupiter-like planets around M-dwarfs (referred to as giant exoplanets orbiting M-dwarfs or GEMS) that challenge these expectations. This thesis investigates the detection, confirmation, and analysis of GEMS through pipeline development and a detailed analysis of two systems.

In Chapter 1, I provide background information …

Multi-Messenger Diagnostics Of The Origin And Transport Of Solar Energetic Particles, Meiqi Wang

Dissertations

Impulsive solar energetic electron events (SEEs) are a common phenomenon originating from the Sun. They are characterized by rapid onset and brief duration, and are commonly associated with solar flares. Solar radio bursts, which offer a rich variety of diagnostic tools for solar activities, exhibits a close relationship with impulsive solar energetic electron events. Such diagnostics are particularly powerful when combined with multi-wavelength remote sensing and in situ observations. The dissertation focuses on combining state-of-the-art microwave imaging spectroscopy data obtained by the Expanded Owens Valley Solar Array (EOVSA) with other multi-messenger observations to investigate the origin of impulsive solar energetic …

Geol 64: Planetary Geology - Syllabus, Dara Laczniak

Open Educational Resources

This Open Educational Resources (OER) syllabus is for an introductory planetary geology course that utilizes results from space missions to expose students to the surface features, composition, geological activity, and probable history of the planets, moons, asteroids, and comets of the solar system. It also places space exploration into the context of larger societal issues such as global warming and natural resource availability and addresses topics such as the ethics of space exploration and hazards of space travel. This OER syllabus aims to foster student-centered learning, critical thinking, data analysis and communication skills, and creativity. Assigned readings are compiled into …

The Core-Collapse Supernovae Particle Physics Interactions, Skylar G. Butler

Beyond: Undergraduate Research Journal

This study investigates the role of specific particle physics interactions in simulations of core collapse supernovae, with a focus on understanding how varying levels of inclusion impact the accuracy of gravitational wave predictions and results of simulations. Different research groups often approach these simulations with varying degrees of complexity, cutting corners by omitting certain reactions or simplifying others. This project systematically evaluates the implications of these choices, comparing the particle physics interactions included, the dimensionality of the simulations, and the governing equations used. Our goal is to identify how these factors influence the precision of numerical simulations. By providing a …

Quantum Error Correction: Studying Correlated Errors On Surface Codes, Reu/Fri Program Physics And Astronomy, Pritesh Thakur

Student Works

No abstract provided.

The Atmospheric Characterization Of Abnormally Blue Early T-Dwarfs Midterm Presentation, Reu/Fri Program Physics And Astronomy, Madalyn Chapleski

Student Works

No abstract provided.

Tabletop Isotropic Source For Neutron Science Training Poster, Reu/Fri Program Physics And Astronomy, Jarom Peterson

Student Works

To develop affordable tabletop neutron sources for neutron science research and education, GS20 scintillator glass doped with Americium-241 is being evaluated inside the BYU Isotropic Fission Chamber (IFC). Our 1985 sample was assessed for radiation damage and found to be in good condition. Neutrons from Am-241 interactions were optically flagged and observed using the IFC in conjunction with the LGB-PVT Neutron Pseudo Spectrometer Detector. Data was recorded via a CAEN desktop digitizer. The analysis code continues to be developed, and the neutron detector will be calibrated using deuterium-deuterium (DD) interactions in the future.

Quantum Ai To Factor Intergers Midterm Presentation, Reu/Fri Program Physics And Astronomy, Kai Sandberg

Student Works

No abstract provided.

Using Novel Technology And Sensemaking In The Classroom, Reu/Fri Program Physics And Astronomy, Julio Escobedo

Student Works

This project looked into the usefulness of various new and unique technologies in a science classroom setting to allow for more sensemaking to occur among students. This was done through professional developments or training for multiple educators on how to use these devices in the classrooms. We found that each new technology had a unique set of useful capabilities and drawbacks. These findings suggest that implementation of these technologies can increase sensemaking if done properly and with proper training beforehand.

The Design Of Coplanar Waveguide Traveling-Wave Kinetic-Impedance Parametric Amplifiers, Jordan Scott Savoie

Master's Theses

Astronomical observations and many physics experiments rely on cryogenic amplifiers for readout. Current sensitivity is limited by the noise figure of high-electronmobility transistor (HEMT) amplifiers, which have proven di!cult to decrease further in recent years. Traveling-wave kinetic-impedance parametric amplifiers (TKIPAs) are an emerging class of amplifiers which have the potential to substantially improve the sensitivity of microwave low-noise amplifiers (LNAs) while also accepting relatively high input powers and amplifying over a wide bandwidth. In this thesis, I present the design, modeling, and testing procedures for coplanar waveguide (CPW) TKIPAs developed by our group at the National Radio Astronomy Observatory. Using …

Self Spin-Orbit Torques, Ryan Greening

Electronic Theses and Dissertations

Spin–Orbit torques (SOTs) provide an energy-efficient pathway to control magnetization in nanoscale heterostructures. Recently, spin-orbit coupling within ferromagnets has been shown to generate self spin-orbit torques (SSOTs) on the magnetization itself. Previous work on self spin-orbit torques relies on thick ferromagnets with complicated film structures with chemical disorder or compositional gradients to generate inversion symmetry breaking. This dissertation advances experimental methodology and presents data on the quantification of self spin-orbit torques in magnetic thin films due to the spin-orbit coupling of standard 3d ferromagnets.

First, I develop an oblique-incidence magneto-optical Kerr effect (MOKE) technique that exploits a mirror-assisted double reflection …

Collaborative Proposal: Caig: Synthetic Data Generation For Solar Energetic Particle Events Via Multimodal Augmentation, Shah Muhammad Hamdi

Funded Research Records

No abstract provided.

Advances In The Morris Observatory In Summer 2025, Mahathir Ahmed Mostafa

Summer Research Showcase

In Summer 2025, the Morris Observatory completed major upgrades to its Meade 16-inch telescope, improving both mechanical functionality and imaging workflows. Hardware enhancements included the installation of a precision focuser, providing finer and more stable focus control, and a flip mirror system, enabling rapid switching between eyepiece viewing and camera imaging without the need for realignment. Imaging and processing approaches were also refined, with systematic use of flats, darks, and lights to correct optical artifacts, sensor noise, and uneven field illumination. Computational methods, developed using Python and Astropy, automated calibration, stacking, and enhancement, increasing consistency and efficiency in image production. …

Development Of A New Ground-Based Instrumentation Technique For Low-Resolution Exoplanet Transmission Spectroscopy, Mary Anne Limbach, Luke M. Schmidt, Ryan J. Oelkers, Darren L. Depoy

Physics & Astronomy Faculty Publications

We present a new instrumentation technique for high-precision, ground-based spectrophotometric measurements ideal for low-resolution (R ∼ 20–60) exoplanet transmission spectroscopy. This technique employs novel thin-film coating technology for wide-band, simultaneous multi-band imaging, enabling high-precision differential photometry through self-referencing and comparison stars. Theoretical calculations and on-sky results show that this method effectively reduces 96% of amplitude scintillation noise and other systematics that typically limit ground-based spectrophotometric precision for bright stars. On-sky results are demonstrated using the custom-built Exoplanet Transmission Spectroscopy Imager (ETSI), deployed at the McDonald Observatory 2.1 m telescope in 2022. For a V = 9.7 mag star, ETSI …

Red Noise Suppression In Pulsar Timing Array Data Using Adaptive Splines, Yi-Qian Qian, Yan Wang, Soumya Mohanty

Physics & Astronomy Faculty Publications

Noise in Pulsar Timing Array (PTA) data is commonly modeled as a mixture of white and red noise components. While the former is related to the receivers, and easily characterized by three parameters (EFAC, EQUAD and ECORR), the latter arises from a mix of hard to model sources and, potentially, a stochastic gravitational wave background (GWB). Since their frequency ranges overlap, GWB search methods must model the non-GWB red noise component in PTA data explicitly, typically as a set of mutually independent Gaussian stationary processes having power-law power spectral densities. However, in searches for continuous wave (CW) signals from resolvable …

The Compositional And Dynamical Properties Of Exoplanets, Cody James Shakespeare

UNLV Theses, Dissertations, Professional Papers, and Capstones

The solid surface density profile of protoplanetary discs, and the composition of these solids, can be formed through sequential condensation models of dust precipitating from the cooling gas of the solar nebula. I continue developing a code that reproduces the chemical compositions of most chondrites as well as the bulk compositions of the rocky planets using our partial condensation model with an evolving disc. I extend this validated code to exoplanet systems with different initial elemental ratios, like the carbon-to-oxygen ratio and estimated stellar abundances over the age of the universe. I have improved this dust condensation code to include …

Orbital Evolution Of The Datura Asteroid Family, Skylar G. Butler

Beyond: Undergraduate Research Journal

To research the Datura Family of asteroids, we used an orbital evolution code to track the orbital decay of asteroid fragments released in an asteroid disruption. Different particle sizes of 10, 100, 500, 750, and 100 micrometers were tracked including the semi-major axis, eccentricity, and inclination in order to observe how certain particle sizes’ orbital elements evolve. Using a young asteroid family like the Datura family gives more insight into the parent asteroid structure and formation because the time is closer to before the asteroid’s breakup. We use these models to constrain the parameters of the dust by comparing the …

Monte Carlo Stellar Evolution Models And Their Application On Globular Clusters, Jiaqi Ying

Dartmouth College Ph.D Dissertations

Stellar evolution models serve as fundamental tools in astronomy, essential for interpreting the interiors and evolutionary stages of stars, and have wide applications in astronomy, from searching for exoplanets to estimating the age of the universe. This thesis explores the inherent uncertainties arising from the complex physics used in stellar evolution models. By adopting a Monte Carlo approach to vary over 20 key stellar evolution parameters, we quantify their impact on model predictions, highlighting substantial influences on age, luminosity, and temperature. Through a detailed analysis of Milky Way globular clusters (GCs), this work rigorously investigates the uncertainties inherent in stellar …

Absence Of Phonon Softening Across A Charge Density Wave Transition Due To Quantum Fluctuations, Yubi Chen, Terawit Kongruengkit, Andrea Capa Salinas, Runqing Yang, Yujie Quan, Fanghao Zhang, Ganesh Pokharel, Linus Kautzsch, Stephen D. Wilson, Sai Mu

Faculty Publications

Kagome metals have emerged as a frontier in condensed matter physics due to their potential to host exotic quantum states. Among these, CsV₃Sb₅ has attracted significant attention for the unusual coexistence of charge density wave (CDW) order and unconventional superconductivity, presenting an ideal system for exploring the emergent phenomena from the interplay of phonons, electronic fluctuations, and topological effects. The nature of CDW formation in CsV3Sb5 is unconventional and has sparked considerable debate. In this study, we examine the origin of the CDW state via ab initio finite-temperature simulations of the lattice dynamics. Through a comparative study …

Rabi Oscillations And Entanglement Between Two Atoms Interacting By The Rydberg Blockade And With A Quantized Radiation Field Studied By The Jaynes-Cummings Model, Francisco D. Santillan, Andreas Hanke

Physics & Astronomy Faculty Publications

The interaction between atoms and a quantized radiation field is fundamentally important in quantum optics and quantum information science. Due to their unusual properties, Rydberg atoms are promising building blocks for two-qubit gates and atom-light quantum interfaces, exploiting the Rydberg blockade interaction which prevents two atoms at close distance (< 10μm) from being simultaneously excited to Rydberg states. Recently, this effect was used to engineer quantum processors based on arrays of interacting Rydberg atoms illuminated by Raman lasers. Motivated by these experiments, we extend the Jaynes–Cummings model to study the interaction between two Rydberg atoms interacting by the Rydberg blockade and a quantized radiation field. We consider both number (Fock) states of the field and single-mode quantum coherent states. In particular, we discuss different types of entanglements between various components of the total system consisting of the two Rydberg-interacting atoms and coherent states of the field, and show that the behavior is significantly different compared to a system with non-interacting atoms corresponding to the two-atom Tavis-Cummings model. Our results are relevant in view of atom-light quantum interfaces as components for future long-distance quantum communication.