Astrophysics and Astronomy Commons^™

Atomistic Characterization Of Hydration-Dependent Fuel Cell Ionomer Nanostructure: Validation By Vibrational Spectroscopy, Dan J. Donnelly, Moon Young Yang, Nicholas Dimakis, Seung Soon Jang, William A. Goddard Iii, Eugene S. Smotkin

Physics & Astronomy Faculty Publications

The development of Nafion alternatives for fuel cells and electrolyzers requires a fundamental understanding of hydration-dependent ion-exchange site acid/base chemistry. We present here reactive force field (ReaxFF) molecular dynamics (MD) simulations of Nafion at varying molar water/ion-exchange-site ratios (λ), which we correlate to our experimental and density functional theory-based vibrational spectra. ReaxFF describes the formation and breaking of covalent bonds, enabling simulations of proton exchange between sulfonic acid/sulfonate groups and water/hydronium. Our MD simulations determine the λ-dependent equilibrium proportions of protonated and deprotonated sites. We find that protonated sites persist across all λ from 0 to 20, challenging the widely …

Using Oblique, Bistatic Receptions Of Superdarn Signals To Measure Hf Propagation In The Auroral And Polar Cap Region, Riley Troyer, Jeffrey Holmes, Evan Thomas, Simon Shepherd, Eugene Dao, John Carilli

Space Dynamics Laboratory Publications

Experiment Geometry

Three receiver locations:

• Pituffik (formerly Thule)
• Utqiagvik (formerly Barrow)
• USCGC Healy – Beaufort Sea

Two SuperDARN locations:

• Christmas Valley (CVE, CVW)
• Iceland (ICE, ICW)

Gnss Technology, Utah State University Space Dynamics Laboratory

Space Dynamics Laboratory Publications

SDL presentation on GNSS Technology

Wide Binary Orbits Are Preferentially Aligned With The Orbits Of Small Planets, But Probably Not Hot Jupiters, S. Christian, A. Vanderburg, J. Becker, A. L. Kraus, L. Pearce, K. A. Collins, M. Rice, Eric L.N. Jensen, D. Baker, V. Bozza, P. Benni, A. Bieryla, A. Binnenfeld, K. I. Collins, D. M. Conti, I. J. M. Crossfield, P. Evans, M. C. Johnson, E. Girardin, J. Gregorio, P. Lewin, T. Mazeh, F. Murgas, A. Panahi, F. J. Pozuelos, D. J. Radford, H. M. Relles, F. Rodriguez Frustaglia, R. P. Schwarz, G. Srdoc, C. Stockdale, T.-G. Tan, W. C. Waalkes, G. Wang, J. Wittrock, S. Zucker

Physics & Astronomy Faculty Works

Studying the relative orientations of the orbits of exoplanets and wide-orbiting binary companions (semimajor axis greater than 100 au) can shed light on how planets form and evolve in binary systems. Previous observations by multiple groups discovered a possible alignment between the orbits of visual binaries and the exoplanets that reside in them. In this study, using data from Gaia DR3 and TESS, we confirm the existence of an alignment between the orbits of small planets (R < 6 R_⊕) and binary systems with semimajor axes below 700 au (p = 10⁻⁶). However, we find no statistical evidence …

Integrating Universal Generative Ai Platforms In Educational Labs To Foster Critical Thinking And Digital Literacy, Vasiliy S. Znamenskiy, Joel Hernandez, Rafael Niyazov

Publications and Research

This study investigates the educational potential of generative artificial intelligence (GenAI) platforms based on large language models (LLMs), such as ChatGPT, Claude, and Gemini, as tools for studentcentred learning. Recognizing the current limitations of GenAI, particularly its propensity for generating inaccurate or misleading information—the paper proposes a novel instructional strategy: an interdisciplinary laboratory designed to foster critical evaluation of GenAI-generated outputs. In this pedagogical model, students engage with GenAI systems by posing questions or solving problems drawn from topics they have already studied and understand. Equipped with correct answers, students are positioned to assess the accuracy and relevance of AI-generated …

The Gauge/Gravity Holographic Duality Between String Theory And Quantum Field Theory: A Full Introduction, Alex A. Short

Physics

The Anti-deSitter Spacetime / Conformal Field Theory (AdS/CFT) correspondence is a well known holographic duality between ten dimensional superstring theories and conformal quantum field theories. The existence of such a correspondence is fascinating and the duality provides a powerful tool-set for working out problems in both string theory and quantum field theory. The correspondence defines a dictionary of terms that exist dual to one another in each theory, allowing theorists to understand the dynamics in one system based on quantities from another. Furthermore, when one side of the duality has strong coupling (meaning the approximations of perturbation theory are no …

Streaming Instabilities In Class 0/I Disks, Shirin Gul Zaidi

Dissertations, Theses, and Capstone Projects

While it is clear that planets form in protoplanetary disks, fragmentation and the radial drift of pebbles inhibit the growth of grains to planetesimals. To overcome these barriers, effective localized dust clumping on a short enough time scale is required. One promising solution to this problem is the streaming instability. Streaming instability is only triggered with a large enough dust-to-gas ratio and grain size. Though it is unknown when and where those conditions are met in protoplanetary disks, recent studies have indicated that planetary cores likely require early formation to match detected exoplanet system masses, so that we need to …

Fast Transients From Magnetic Disks Around Non-Spinning Collapsar Black Holes, Justin A. Bopp

Dissertations, Theses, and Capstone Projects

Most black holes (BHs) formed in collapsing stars have low spin, though some are expected to acquire a magnetic accretion disk during the collapse. While such BH disks can launch magnetically driven winds, their physics and observational signatures have remained unexplored. We present global 3D general relativistic magnetohydrodynamic simulations of collapsing stars that form slowly spinning BHs with accretion disks. As the disk transitions to a magnetically arrested state, it drives mildly relativistic, wobbling, collimated magnetic outflows through two mechanisms: steady outflows along vertical magnetic field lines (“Blandford-Payne jets”) and magnetic flux eruptions. With isotropic-equivalent energy of E_iso ≈10 …

Search For Gravitational Waves Emitted From Sn 2023ixf, A. G. Abac, R. Abbott, Teviet Creighton, Mario C. Diaz, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present the results of a search for gravitational-wave transients associated with core-collapse supernova SN 2023ixf, which was observed in the galaxy Messier 101 via optical emission on 2023 May 19, during the LIGO–Virgo–KAGRA 15th Engineering Run. We define a five-day on-source window during which an accompanying gravitational-wave signal may have occurred. No gravitational waves have been identified in data when at least two gravitational-wave observatories were operating, which covered ∼14% of this five-day window. We report the search detection efficiency for various possible gravitational-wave emission models. Considering the distance to M101 (6.7 Mpc), we derive constraints on the gravitational-wave …

Exploring The Enstatite Chondrites: Modal Abundances, Metamorphic History, And Volatile Challenges, Mabel Gray

Dissertations, Theses, and Capstone Projects

This thesis investigates the formation conditions, thermal histories, and volatile inventories of enstatite chondrites (ECs). A diverse set of ECs is analyzed to capture the broad variability within this meteorite class. Chapter 1 presents a comparative analysis of mineral abundances using automated point counting, X-ray diffraction analysis, and XMapTools-based phase mapping. The results reveal significant variations in silicate and sulfide abundances across EC groups, challenging the conventional binary classification and suggesting distinct formation conditions. Chapter 2 explores the thermal histories of two highly equilibrated EH chondrites, proposing a novel formation mechanism on the parent asteroid: contact metamorphism driven by an …

Artificial Intelligence And Astronomy: Lab Manual For Generative Ai-Based Learning Activities, Vasiliy Znamenskiy

Open Educational Resources

This laboratory manual introduces an innovative approach to teaching astronomy by integrating generative artificial intelligence (AI) tools into hands-on educational activities. Aimed at undergraduate and general education students, the manual guides learners through interactive exercises that involve evaluating AI-generated text responses, creating scientifically inspired images, and producing short educational videos about astronomical phenomena. By engaging with platforms such as ChatGPT, Gemini, DALL·E, and InVideo, students develop critical thinking skills, enhance their digital literacy, and deepen their understanding of space science. The method emphasizes inquiry-based learning, creativity, and scientific communication, preparing students to become thoughtful users of AI in academic and …

Near-Earth Object (Neo) Surveyor Introduction “Neos”, Brent Carlsen

Space Dynamics Laboratory Publications

NEOS

- Near-Earth Object Surveyor (NEOS)

- Its Mission

- Its Importance

- How it’s built

- What you will see today

• Where piece parts were made
• Where it will be assembled
• Where it will be tested

Enhanced Nuclear Binding Near The Proton Drip Line Opens Possible Bypass Of The 64Ge Rapid Proton Capture Process Waiting Point, Zachary Meisel, W.-J Ong, J. S. Ranhawa

Faculty Publications

We performed astrophysics model calculations with updated nuclear data to identify a possible bypass of the ⁶⁴Ge waiting point, a defining feature of the rapid proton capture (rp) process that powers type I X-ray bursts on accreting neutron stars. We find that the rp-process flow through the 64Ge bypass could be up to 36% for astrophysically relevant conditions. Our results call for new studies of ⁶⁵Se, including the nuclear mass, β-delayed proton emission branching, and nuclear structure as it pertains to the 64As(p, γ) reaction rate at X-ray burst temperatures.

A Catalytic Pathway For The Formation Of Cyanobenzene In Nitrogen-Rich Environments And The Spectroscopy Of The Reactive Intermediates, Vincent J. Esposito, Silvia Alessandrini, David Dubois, Ryan Fortenberry

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The catalytic reaction of isocyanobenzene (C₆H₅NC) with NCN⁻ produces cyanobenzene (C₆H₅NC) through various highly stable reactive intermediate species. Nitrogen-rich environments such as Titan’s atmosphere serve as favorable locations to study reaction pathways involving nitrogenated species contributing to organic growth. Formation pathways of cyanobenzene have been characterized, but none with the contribution of anions or phenyl groups. In regions with a high abundance of nitrogen anions, such as Titan’s atmosphere, reactions with species such as NCN⁻ may play a role in the formation of cyanobenzene. Highly accurate computational methods are used …

Challenging $\Lambda$Cdm: Unraveling Cosmic Distances, Dark Sector Phenomenology, And Alternative Primordial B-Mode Sources, Kylar L. Greene

Physics & Astronomy ETDs

The dominant Lambda Cold Dark Matter (LCDM) cosmological model, while remarkably successful, increasingly shows signs that it may not fully describe our Universe, as persistent tensions in expansion rates and structure formation remain unresolved. In this thesis, I challenge the LCDM paradigm using novel theoretical frameworks combined with rigorous numerical analyses. I demonstrate that the expansion-rate tension fundamentally reflects underlying distance disagreements, and that the Thomson scattering rate strongly restricts higher pre-recombination expansion rates without additional physics. Further, I present a novel cosmological model using a mirror dark sector and varying fundamental constants, revealing an observational degeneracy allowing significantly higher …

Cross-Correlation Studies Of The Cosmological 21 Cm Signal And High-Redshift Galaxy Distributions, Simon Matin

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Epoch of Reionization (EoR) marks a critical phase in cosmic history, during which time the first stars and galaxies ionized the surrounding neutral hydrogen gas. A powerful way to probe this period is by cross-correlating the 21 cm signal from neutral hydrogen with high-redshift galaxy distributions. In this study, we analyze the 21 cm-galaxy cross-power spectrum using simulated sky maps and explore its redshift evolution, revealing a transition from positive correlation at early times (high redshift) to anti-correlation at later stages of reionization (low redshift). Our results highlight the sensitivity of the cross-power spectrum to the evolving ionized structure …

On Efficient Position Dependent Computation Of Radiation Near Accretion Disks, Kara Jeanette Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Accretion onto super massive black holes (SMBH) plays a vital role in explaining our observations of active galactic nuclei (AGN). One key aspect of observations of AGN is the prevalence of massive outflows which transport matter and energy away from the galactic core. These outflows are characterized by highly blueshifted absorption lines as radiation from the accretion disk is absorbed by gas which is moving toward us. Radiation pressure on spectral lines is expected to play a vital role in launching and accelerating these winds. At the other end of the spectrum of black hole masses, accretion disks in X-ray …

Quasi-Normal Modes Of Extended Uncertainty Principle Kerr Black Holes, Ava Hoeger, Jonas Mureika

Honors Thesis

The current understanding of gravity is shaped largely by Albert Einstein’s theory of General Relativity. This theory is highly successful at predicting phenomenon on macroscopic scales, but it faces unphysical singularities at quantum scales. This thesis will explore the possibility of combining General Relativity with quantum mechanics through the Extended Uncertainty Principle (EUP), which provides a new, fundamental length scale correction to the Heisenberg Uncertainty Principle. This allows for quantum gravity effects at macroscopic scales, which will be examined through Kerr black holes with event horizons on the order of . These black holes are rotating and electrically neutral, and …

Mass Transfer In Binary Stars, Pierson Lipschultz

COD Library Student Research and Award Symposium

I investigated the properties of mass transfer in binary star systems. I feature results from Vela X-1, V404 Cygni, and W Ursae Majoris as well as corroborating data from POSYDON. Furthermore, I found the local populations on an HR diagram of each system. Additionally, I found anomalous data properties in both MESA and V404 Cygni which warrant further investigation.

Faculty Sponsor: Professor Joseph DalSanto

Observational Properties Of Near-Maximal Spin Black Holes With The Eht, Tegan A. Thomas, Angelo Ricarte, Yajie Yuan

Senior Honors Papers / Undergraduate Theses

In 2021 and 2024, the Event Horizon Telescope (EHT) collaboration published the first polarized images of the supermassive black holes (SMBHs) M87* and Sgr A*, which allowed us to place important constraints on the accretion flow and underlying space-time. Of particular interest is the dimensionless spin parameter "a_•", which theoretically may attain a maximum value of a_• = 0.998 when spun up by a thin accretion disk. On the other hand, mechanisms including incoherent accretion, SMBH mergers, and spin extraction via jets, are hypothesized to spin down SMBHs from these near-extremal values. In this work, we perform …