Astrophysics and Astronomy Commons^™

Light Nuclei Femtoscopy And Baryon Interactions In 3 Gev Au+Au Collisions At Rhic, The Star Collaboration

Physics and Astronomy Faculty Publications

We report the measurements of proton-deuteron (𝑝-𝑑) and deuteron-deuteron (𝑑-𝑑) correlation functions in Au+Au collisions at √𝑠NN = 3 GeV using fixed-target mode with the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). For the first time, the source size (𝑅 𝐺), scattering length (𝑓0), and effective range (𝑑0) are extracted from the measured correlation functions with a simultaneous fit. The spin-averaged 𝑓0 for 𝑝-𝑑 and 𝑑-𝑑 interactions are determined to be -5.28 ± 0.11(stat.) ± 0.82(syst.) fm and -2.62 ± 0.02(stat.) ± 0.24(syst.) fm, respectively. The measured 𝑝-𝑑 interaction is consistent with theoretical calculations and low- energy scattering experiment …

Electric-Charge-Dependent Directed Flow Splitting Of Produced Quarks In Au+Au Collisions, The Star Collaboration

Physics and Astronomy Faculty Publications

We report directed flow (𝑣1) of multistrange baryons (Ξ and Ω) and improved 𝑣1 data for 𝐾−, ̄ 𝑝, ̄ Λ and 𝜙 in Au+Au collisions at √𝑠NN =27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (“splitting”) for combinations having non-identical quark content. Under the assumption of quark …

Measurement Of Directed Flow In Au+Au Collisions At √Snn = 19.6 And 27 Gev With The Star Event Plane Detector, Star Collaboration

Physics and Astronomy Faculty Publications

In heavy-ion collision experiments, the global collectivity of final-state particles can be quantified by anisotropic flow coefficients (vn). The first-order flow coefficient, also referred to as the directed flow (v1 ), describes the collective sideward motion of produced particles and nuclear fragments in heavy-ion collisions. It carries information on the very early stage of the collision, especially at large pseudorapidity (η), where it is believed to be generated during the nuclear passage time. Directed flow therefore probes the onset of bulk collective dynamics during thermalization, providing valuable experimental guidance to models of the pre-equilibrium stage. In 2018, the Event Plane …

Suntan (And Other Solar Tigonometric Functions), John Adam

Mathematics & Statistics Faculty Publications

Question 1: If I₀ is the solar irradiance (power per unit area, W/m²) reaching my head, express the intensity on the side of my face (I_s) in terms of θ. Assume for now that the irradiance is independent of path length through the atmosphere and that my face is normal to the direction θ = 90°.

Using the 1962 U.S. Standard Atmosphere,² Hottel (1976)³ expressed the solar irradiance using the formula

I = I₀(a₀ + a₁e^{−k sec θ}), where A is the elevation in kilometers and

a₀ = 0.4237 − 0.00821(6 − A)²; a₁ = 0.5055 …

The B³Π–A³Δ And B³Π–X¹Σ+ Band Systems Of Zro, Manish Bhusal, Peter F. Bernath, Jacques Liévin, Léo Lavy

Chemistry & Biochemistry Faculty Publications

The zirconium oxide (ZrO) b³Π–a³Δ system is a prominent source of opacity in the atmospheres of S-type stars in the near-infrared region. The emission spectra of ZrO, obtained at the National Solar Observatory located at Kitt Peak in Arizona, have been utilized to analyze this band system. A reanalysis of the 0–0 vibrational band of the b³Π–a³Δ transition has been carried out. For the first time, the vibrational bands with 1 ⩽ v ′ ⩽ 3 and v″ ≤ 4 for the same electronic transition have been rotationally analyzed using PGOPHER. Additionally, the 0–0 and 1–1 bands of the spin-forbidden …

Nonlinear Wave Dynamics In Asteroseismology With Application To Delta Scuti Stars, Mohammed Mourabit

Physics Dissertations - Archive

This thesis compiles the collection of works in nonlinear astroseismology and its implication to the δ Sct variable that we carried over the course of five years. With the advent of high-resolution space missions such as the Kepler and TESS telescopes, we were able to see significant progress in the field in recent years. Nonetheless the new technologies also brought an increasing number of observation that are seemingly contradictory to the linear theory of asteroseismology. In particular, we find the δ Sct variable, which eludes our models in terms of how varied we find they spectra for stars with very …

Boy Whose Head Was Filled With Stars: A Life Of Edwin Hubble (2021) By Isabelle Marinov, Maughn Rollins Gregory

Picture Books

Barely a hundred years ago, Edwin Hubble changed the way we understand the universe and our place in it more dramatically than almost anyone else has ever done. As this picture book biography shows, his mind-boggling discoveries can be traced back to childhood questions. The discovery that the world is bigger than we had imagined happens in many ways, and learning that we have some choices in deciding how new facts, new experiences, and new perspectives can matter to us is a necessary part of education.

Evaluation Of The Stability Of Argan Oil Nanoemulsions Formulated And Optimized Through Experimental Design For Dermatological Applications, Yousra Mdarhri, Ikram Bouziane, Narjisse Mokhtari, Lama Rissouli, Ahmed Touhami, Fakhita Touhami, Mohamed Chabbi

Physics & Astronomy Faculty Publications

Argan oil is a highly sought-after natural product renowned for its therapeutic and rejuvenating properties. This study focused on harnessing its dermatological bioactivity by developing stable nanoemulsions through a simple low-energy method using a single non-ionic surfactant. The composition and properties of Argan oil were analyzed using High-Performance Liquid Chromatography (HPLC), Gas Chromatography (GC), and quality indexes, adhering to international standards. The effect of system composition on stability was evaluated using a pseudo-ternary phase diagram and Phase Inversion Composition (PIC) emulsification technique. Optimal process parameters for producing stable nanoemulsion were determined through Response Surface Methodology (RSM) analysis. The resulting nanoemulsions …

A Compact Frequency Comb Generator For Large-Format Superconducting Microwave Kinetic Inductance Detectors, Sungyoun Seo

Open Access Master's Theses

Microwave Kinetic Inductance Detectors (MKIDs) are promising superconducting detectors that achieve superior sensitivity to silicon-based photo detectors by leveraging a small bandgap of superconductors. They are advantageous for sensitive imaging instruments, particularly space telescopes. However, a large-format array with several hundreds of thousands of detectors is required for large-scale observations in space, and it encounters multiple challenges. The biggest challenge is the absence of compact, energy-efficient, and radiation-tolerant readout solutions. Of multiple functions in the MKID readout, the new frequency comb generator is presented in this thesis. It features a low on-chip memory requirement while promising the relaxed frequency resolution …

Hardware Implementation Of An Efficient Frequency Comb Generator For Microwave Kinetic Inductance Detectors, Frank Atobrah Danso

Open Access Master's Theses

The frequency comb generator is an essential component in the readout of superconducting detectors. This component is responsible for generating the resonant frequencies necessary to detect photon interaction with the detectors. This component however has not received the much needed attention in terms of readout systems optimization. Conventional implementations rely on either inverse fast Fourier transform (IFFT) engines, which scale poorly in power with increasing frequency resolution requirement but allow flexible tone updates, or lookup tables (LUTs), which demand large memory for high frequency resolution.

Microwave Kinetic Inductance Detectors (MKIDs) are superconducting detectors which have gained significant interest for cryogenic …

Stars, Statutes, And Sharing: Designing Global Ip Frameworks For Space-Based Discoveries, Ed Koellner

Marquette Intellectual Property & Innovation Law Review

As humanity stretches farther into space physically, commercially, and intellectually, contemporary legal frameworks are beginning to creak under the pressure. Intellectual property laws seem to be playing catch-up. Those laws were written for a world bound by borders and gravity, not for orbital labs, the Earth’s Moon, or AI-generated inventions drifting above the Earth.

This article takes a closer look at the increasingly complex intersection of space law, intellectual property, and artificial intelligence. This domain is no longer reserved for state-led missions or high-level treaties. Now and in the near future, a university lab or a private startup might be …

Three-Dimensional Spreading Of Magnetic Reconnection Between Non-Parallel Flux Ropes With A Guide Field, Regis John

Graduate Theses, Dissertations, and Problem Reports (ETD)

Magnetic reconnection is a fundamental plasma process that facilitates the rapid conversion of magnetic energy into particle acceleration, plasma flows, and heating. It plays a central role in explosive astrophysical events such as solar flares, where vast amounts of magnetic energy are released on short time scales. A key structure in many reconnection sites is the magnetic flux rope, a column of plasma carrying current threaded by helical magnetic fields, which is frequently involved in or generated by reconnection. Understanding how reconnection unfolds in such flux rope systems is critical for interpreting both space weather phenomena and laboratory plasma dynamics. …

Rapid Inference Of Atmospheric Feature Parameters From Light Curves Using Bayesian Neural Networks, Eugenio A. Diaz

Honors Undergraduate Theses

Mapping atmospheres using rotationally modulated light curves offers insights into cloud structures and dynamics. Current retrieval methods, primarily based on Markov Chain Monte Carlo (MCMC) techniques like Aeolus, can infer atmospheric features but are computationally prohibitive for large datasets. This project proposes a neural network (NN) framework for the rapid, variational inference of atmospheric structure from light curves, particularly those of brown dwarfs. The primary approach focuses on training a Bayesian NN (BNN) to perform regression, predicting the spot parameters that describe the object's surface brightness map. Given the scarcity of suitable observational training data, the BNN is trained on …

Dual View Of The Z2-Gauged Xy Model In 3d, Piers Coleman, Anatoly Kuklov, Alexei Tsvelik

Publications and Research

The Z₂ gauged XY model is of long-standing interest both in the context of nematic order, and the study of fractionalization and superconductivity. This paper presents heuristic arguments that no deconfinement of the XY field occurs in this model and presents results of a large-scale Monte Carlo simulations on a cubic lattice which are consistent with this conclusion. The correlation radius determining the confinement is found to be growing rapidly as a function of the parameters in the phase featuring the nematic order. Thus, mesoscopic properties of the system can mimic deconfinement with high accuracy in some part of …

Uncertainty In Solar Wind Propagation: An Analysis Of L1 To Earth Variability And The Implications For Geospace Modeling In Space Weather Operations, Espen T. Fredrick

Physics Dissertations - Archive

As humanity's technological dependence grows, so does its vulnerability to space weather. Space weather describes solar-driven phenomena in the near-Earth space environment and their terrestrial effects. Many of these effects occur due to the interaction of the solar wind and Earth's magnetosphere. The solar wind originates at the solar corona and carries solar plasma and magnetic field outward through the solar system. This magnetic field, known as the interplanetary magnetic field (IMF) during transit, can undergo magnetic reconnection with Earth's geomagnetic field when oppositely aligned field lines converge. This process transfers energy into Earth's magnetosphere, driving space weather phenomena.

Space …

Characterizing The Earth's Magnetosheath With In Situ Measurements, Hector A. Salinas

Physics Dissertations - Archive

Earth’s magnetosheath is a region of shocked plasma that mediates energy and momentum transfer from the solar wind to the magnetosphere. The dynamics and thus the plasma structures of this region are highly dependent on upstream solar wind conditions. As such, the region is often characterized as a turbulent environment, with the most intense periods of turbulence occurring often under quasi-parallel bow shock conditions. This magnetosheath turbulence displays as variable and large-scale fluctuations with in-situ measurements. Given that turbulence is a characteristic feature of the magnetosheath, this dissertation asks two questions: (1) How are plasma structures inside the sheath affected …

On The Orbital Dynamics Of Exoplanets, Exomoons, And Submoons, Shaan Dharmesh Patel

Physics Dissertations - Archive

Although exoplanet detection has long been a central focus in astronomy, growing interest in exomoons has highlighted the increasing need for theoretical frameworks to interpret emerging candidates. Furthermore, while submoons, natural satellites orbiting moons, are not presently observed in the Solar System and remain speculative (e.g., the hypothesized past submoon of Saturn’s Iapetus), their existence is plausible within the context of the complex and diverse architectures now identified across planetary and stellar systems. We develop a generalized framework to assess the orbital stability of exomoons and submoons through comprehensive N-body simulations incorporating both three-body dynamics and tidal interactions, with the …

Archival Stellar Flare Follow-Up In Evryscope Observations, Tyler J. Thomas

Honors Undergraduate Theses

M dwarfs, the most abundant stars in the galaxy, are prime targets in the search for habitable exoplanets. However, their high flare activity may compromise planetary atmospheres, with Coronal Mass Ejections (CMEs) increasing this risk. Despite this, the relationship between M dwarf flares and CMEs is not well understood. This study uses archival data from Evryscope North and South, crossmatched with Sloan Digital Sky Survey (SDSS) and Gaia data, to investigate this relationship. This crossmatching demonstrated an abundance of stars within the 20 arcsecond Evryscope uncertainty. The analysis also revealed a modest excess of K1 and F9 type stars but …

Reconnection-Driven Electron Acceleration, Ripudaman Singh Nirwan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Magnetic reconnection converts the magnetic energy available in a plasma to the kinetic energy of its constituent particles. In the simplest case, it occurs between anti-parallel magnetic field lines meeting in a plane. Another variant known as ‘component reconnection’ involves field lines reconnecting at an angle, giving a non-zero magnetic field component perpendicular to the plane of reconnection. This component is known as the ‘guide field’ and it is normalized to the reconnecting field in the literature. The guide field controls the particle-scale dynamics of reconnection and influences the ensuing particle acceleration.

Component reconnection occurs in the Earth’s magnetosphere, along …

The Origin And Properties Of Ionized Gas In The Inner Milky Way Disk, Dylan J. Linville

Graduate Theses, Dissertations, and Problem Reports (ETD)

The interstellar medium (ISM) plays a crucial role in the evolution of the Milky Way and other spiral galaxies, but numerous gaps remain in our collective understanding of its properties. The now-complete Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) and the ongoing extension, the GBT Diffuse Ionized Gas Survey at Low Frequencies (GDIGS-Low), offer the opportunity to study the ionized component of the ISM at unmatched sensitivity and resolution. In this dissertation I will utilize GDIGS and GDIGS-Low data to improve our understanding of discrete regions of ionized gas. I first use GDIGS to provide improved measurements of …

Modeling Relativistic Fluids In Dynamical Spacetimes, Terrence Alphonse Pierre Jacques

Graduate Theses, Dissertations, and Problem Reports (ETD)

Multi-messenger astrophysics opens a new era in our understanding of the most dynamic and energetic systems in the Universe. Correlating gravitational-wave and electromagnetic signals in space and time enables stringent tests of models for core-collapse supernovae, merging supermassive black-hole binaries with accretion disks and jets, and mergers of compact object binaries such as binary neutron stars (BNS) and white dwarfs. Comparisons between models and multi-messenger observations may be used to constrain the neutron-star equation of state (EOS), formation channels for compact-object binaries, and emission mechanisms behind short gamma-ray bursts.

In modeling such astrophysical systems, great success has been achieved by …

From Bobcat To Bursts: Multi-Messenger Constraints On Supermassive Black Holes And Binaries, Jessica Sydnor

Graduate Theses, Dissertations, and Problem Reports (ETD)

Supermassive black hole binaries (SMBHBs) are a natural consequence of hierarchical galaxy formation and evolution. When galaxies merge, their central supermassive black holes (SMBHs) are expected to form bound pairs that evolve from kiloparsec to sub-parsec separations under the influence of dynamical friction, stellar scattering, and gas dynamics. Ultimately, these SMBHs reach the regime where gravitational wave emission dominates and drives the final inspiral and coalescence. Understanding the formation, evolution, and observational signatures of SMBHBs is critical to advancing multi-messenger astrophysics, particularly in the era of pulsar timing arrays (PTAs) and the upcoming Laser Interferometer Space Antenna (LISA), which opens …

Response Of Galactic Disks To Dark Matter Halo Triaxiality, Alex J. Hutton

College of Graduate Studies: Theses & Dissertations

In this study we examine the influence of dark matter halo triaxiality on the evolution of galactic disks. We do this by running a series of collisionless N-body models. In a first set of models we place the galactic disk within an oblate halo at various orientations and examine the resulting evolution. In our second set we construct fully self-consistent models of a stellar disk embedded within a spherical halo, with an impacting external dark matter dwarf galaxy. After evolving the simulations for a Hubble time, we examine the disk orientation and warping along with other quantities such as bar …

The Presence Of Outer Giant Planets And Their Role In Inner Planet Formation With And Without Their Influence, Mateo E. Guerra Toro

Graduate Theses/Dissertations

We performed dynamical simulations of the giant impact phase of planet formation to investigate the formation of inner terrestrial planets under the influence of 4 solar system-like outer giant planets. We developed a new code using the N-body simulation suite REBOUND and REBOUNDx (Rein et al. (2019) and Tamayo et al. (2019)) to simulate 2 stages of planetary formation: a residual gaseous protoplanetary disk phase and subsequent dynamical evolution after the disk photoevaporates. The initial conditions for the inner planetary embryos were taken by Morrison et al. (2020) based on a range of solid surface densities that produced Super-Earth terrestrial …

Line List For The A²Π−X²Σ⁺ And The B²Σ⁺−X²Σ⁺ Band Systems Of Caf, Léo Lavy, Peter F. Bernath, Adam Pastorek

Chemistry & Biochemistry Faculty Publications

The spectral analysis of molecule-rich asymptotic giant branch (AGB) stars is challenging. Although other calcium and fluorine bearing molecules are observed in the microwave and in the visible spectrum of AGB stars, CaF has never been detected, despite favorable chemical equilibrium predictions. Yet, measuring the CaF abundance could give more insight into the fluorine budget of AGB stars and allow better simulation of stellar spectra. In this work, we present an analysis of the visible spectrum of CaF obtained with a Fourier transform spectrometer. CaF A²Π−X²Σ⁺ and B²Σ⁺−X²Σ⁺ band systems were excited with a hollow cathode discharge. Using previous fluorescence …

Collision-Induced Absorption Spectra Of N₂ And Ch₄, Ryan M. Johnson, Peter F. Bernath, Brant Billinghurst, Jianbao Zhao

Chemistry & Biochemistry Faculty Publications

Collision-induced spectra are essential for radiative transfer modeling of Titan's atmosphere. We present experimental spectra of nitrogen–methane mixtures with an accompanying fit of N₂-CH₄ collision-induced absorption in the 30–400 cm⁻¹ region at about 130 K. We found a peak absorption of 2.30 × 10⁻⁵ cm⁻¹ amagat⁻² at 75 cm⁻¹ and a secondary peak of 1.35 × 10⁻⁵ c⁻¹ amagat⁻² at 206.5 cm⁻¹, which agrees with previous studies. Our work does not support the suggestion that N₂-CH₄ CIA in the far-infrared should be increased by about 50%, as suggested by spectroscopic modeling of Titan using data from A. Borysow & C. …

Unraveling Visible Spectra Of S-Type Stars: The F3Δ–A3Δ (Α System) And E3Π–A3Δ (Β System) Band Systems Of Zro, Manish Bhusal, Peter Bernath, Jacques Liévin

Chemistry & Biochemistry Faculty Publications

ZrO has many low-lying states, and its spectra are essential for the characterization of S-type stars. A high-resolution emission spectrum recorded with a Fourier transform spectrometer at the National Solar Observatory is used for the analysis. The 0–0 and 1–0 bands of the f³Δ-a³Δ system (α system) and the 0–0 band of the e³Π-a³Δ system (β system) have been rotationally analyzed using the modern spectral fitting program PGOPHER. New ab initio calculations of transition dipole moments have been performed to determine the band strengths. These band strengths are used to produce line lists that are suitable for the …

Precision Measurement Of The Muon’ S Anomalous Precession Frequency Using Energy Integrated Analysis In The Fermilab Muon G- 2 Experiment, Joseph Peck

Theses and Dissertations--Physics and Astronomy

This dissertation investigates the anomalous magnetic moment of the muon, aµ, through the Fermilab Muon g -2 Experiment, which aims to measure aµ to a precision of about 140 parts-per-billion.

Muons were injected into a magnetic storage ring where their decay positrons were detected by calorimeters. The changing spin and momentum orientation leads to an oscillation in decay positron counts, known as the anomalous precession frequency ! a. Using the magnetic field and !a measurements, we can determine the value of a µ. This study focuses on the Q-Method determination of !a, which utilizes an energyintegrated reconstruction rather than high-energy …

A Multidisciplinary Approach To The Thermal And Non-Thermal Mechanisms In Galaxy Clusters, Sheng-Chieh Lin

Theses and Dissertations--Physics and Astronomy

Galaxy clusters form at the intersections of the cosmic web and carry imprints of the structure formation history of the universe. As massive, multi-component systems, they offer unique insights into the astrophysical processes that govern both structure formation and galaxy evolution. Observable across the full electromagnetic spectrum, clusters emit photons through a variety of mechanisms, each tracing different physical processes. This dissertation investigates both the thermodynamic and non-thermal properties of the intracluster medium (ICM) to better understand the physical processes shaping observed phenomena. It comprises three main studies, each targeting a different aspect of galaxy cluster physics. In the second …

A Time-Dependent Spectral Analysis Of Γ Cassiopeiae, Sean J. Gunderson, David P. Huenemoerder, José M. Torrejón, Dustin K. Swarm, Joy S. Nichols, Pragati Pradhan, Richard Ignace, Hans Moritz Guenther, A.M.T. Pollock, Norbert S. Schulz

Publications

We investigated the temporal and spectral features of γ Cassiopeiae’s X-ray emission within the context of the white dwarf (WD) accretion hypothesis. We find that the variabilities present in the X-ray data show two different signals, one primarily due to absorption and the other due to flickering like in nonmagnetic cataclysmic variables. We then use this two-component insight to investigate previously unreported simultaneous XMM and NuSTAR data. The results of model fitting find WD properties consistent with optical studies alongside a significant secondary, thermal source. We propose a secondary shock between the Be decretion disk and WD accretion disk as …