Astrophysics and Astronomy Commons^™

Effects Of The Gravity Gradient On The Path Of 1i/‘Oumuamua, Hannah R. Richardson

Honors Theses

In October 2017, the asteroid 1I/’Oumuamua first passed into viewing range [1]. The asteroid is notable for being the first interstellar object to enter the solar system. 1I/’Oumuamua was also unusual in its geometry; it is thought to have an aspect ratio of 6:1 and a length of approximately 400 m [2] [3]. The asteroid was observed to experience a non-Keplerian acceleration estimated to be on the order of 1⇥10−6 m s2 . Several theories have been proposed for the cause of this acceleration, all of which are non-gravitational in nature: volatile outgassing, photon pressure, and solar winds [1][4]. However, …

The Search For Slow Particles And Magnetic Monopoles With Nova, John Clark

Honors Theses

Singular magnetic poles, north or south, have been theorized to exist for hundreds of years. In the modern day, the elusive singular magnetic pole still remains undiscovered. The appearance of this particle would help confirm many Grand Unified Theories, GUTs, and revolutionize our understanding of some of the fundamental forces of the universe. Fermilab's NOvA collaboration is working on ways to screen and detect magnetic monopoles and other slow-moving particles coming from outer space alongside their main mission to study neutrinos. The aim of this work is to determine and improve the Far Detector’s efficiency at identifying slow moving particles. …

An Integrative Approach To Einstein’S Field Equations Of General Relativity For High School Students, Christina M. Aintablian

Senior Honors Theses

Einstein’s Field Equations form the foundation of the theory of General Relativity, describing the interdependence of mass-energy and spacetime curvature, where curvature gives rise to gravity. However, the complexity of these equations makes them difficult for high school students to grasp. The mathematical framework of General Relativity is introduced step by step, beginning with relative motion and culminating in a discussion of complex phenomena that challenge modern physics. Each explanation intertwines core concepts of relativity with pre-established mental models to enhance learning. Through the use of figures, analogies, narratives, and thought experiments, a structured framework is developed to make relativity …

Simulations Of Magnetar Spin-Down Lifetimes Using Magnetic Braking Models, Sophie Wessel

Honors College Theses

The beginnings of magnetar lifetimes are not very well understood. It is important to improve our understanding of magnetar origins in order to investigate possible evolutionary connections to other classes of NS, such as X-ray dim isolated NSs (XDINSs). Here we follow in the steps of another paper1 in modeling the spin evolution of magnetars, utilizing two avenues of evolution: one involving exponential B-field decay, and the other involving suband super-exponential B-field decay. We replicate the results of the paper, utilizing Monte Carlo methods to generate and evolve synthetic populations of magnetars, which are then compared to the current known …

Impact Of Magnetic Fields On Cosmic Ray Density In Molecular Clouds, Byron Jesus Encinas Velazquez

Open Access Theses & Dissertations

We investigate the effects caused by Cosmic Rays (CRs) in a Molecular Clouds (MCs) environment and the effects of varied magnetic field configurations in the core (r = 1 Pc ) of a MC. We take as initial conditions for the interstellar medium a product of various supernova explosions as injected initial perturbation and observe the evolution during the timescale of ~4.5 Myrs. We compute the CR reduction factor R as a measure of the density of a distribution of particles traveling with a guiding center along randomized field lines near the core and discuss their impact on the ionization …

Probing The 'Mev Gap': Discovery And Characterization Of Persistent And Transient Mev-Gev Gamma-Ray Sources With The Fermi Large Area Telescoope, Scott Joffre

All Dissertations

The MeV Gap is a moniker for the energy regime E~0.1-100 MeV that has lacked sensitive observations for the last 20 years. This is not out of scientific disinterest, but observational challenges. The only instrument currently available to make observations in the MeV Gap is the Fermi Large Area Telescope (LAT). For the first time ever, Fermi-LAT has been leveraged to push its observational capabilities to its absolute lower energy limit to end this 20-year observational gap. Observing the MeV sky is imperative for identifying some of the most luminous galaxies in the Universe known as blazars. The brightest blazars …

The Effect Of Nuclear Isomers On S-Process Nucleosynthesis, Jaad Tannous

All Dissertations

s-Process nucleosynthesis is a process in which stars produce elements of mass range A = 57 to 210. Since the days of B2FH, immense work has gone into quantifying and computing s-process yields and pathways. We expand upon said work along two fronts. The first front sets up the framework for proper treatment of nuclear isomers in network calculations. We apply the framework to study 85Kr, which is a pivotal isotope in the s-process chain that affects the abundance yields of Strontium and Rubidium isotopes. In particular, we are interested in the ratio of 88Sr/86Sr and 87Rb which are important …

A Spectroscopic Survey Of Atmospheres Of Super-Earths, Luke Brust

Honors Theses

Recent research has made it possible to use spectroscopy to analyze the composition of the atmospheres of exoplanets, planets that orbit other stars. Most projects thus far have focused on the atmospheres of gas giants, as it is less challenging to observe them with available equipment. This project studies the atmospheres of four Super- Earths, planets that have a mass greater than the Earth but smaller than Neptune. This is accomplished by processing the raw spectroscopic data from the Hubble Space Telescope and modeling the atmosphere using the program 𝝉-Rex3. This survey found clear results from two of the selected …

Constraining Neutron Star Kicks Through Gravitational Wave Detection, James Phillips

Graduate Theses and Dissertations

Neutron stars have, on average, much higher proper motions than those of hot and bright O and B type main sequence stars. Thus, it is widely suspected that asymmetries in core-collapse supernovae provide a substantial kick to these compact objects at birth. Gen- eral Relativity predicts that such supernova asymmetries will generate bursts of gravitational radiation, though no such burst has been yet detected. Here we argue that the polarization amplitudes of those gravitational waves can be used to calculate the kicks imparted on that nascent neutron star. We begin by reviewing the evidence for natal kicks, then we describe …

Dissolving Sand Into Fog - Portraying Long Term Temporal Illusions Through Music, Kyle Bergler

Honors Projects

Long-term temporal illusions permeate our day-to-day lives, but due to their highly subjective nature, few are familiar with them. To help introduce these topics in a way that lets a wider audience connect individually with them, I composed three works for percussion ensembles, each in a different style, and each portraying one or multiple long-term temporal illusions. All of these pieces were composed and rehearsed throughout the spring 2025 semester and premiered at my senior recital on April 19, 2025.

Global Ionospheric F Region Parameters From Gnss-Pod Limb Measurements: Evaluations And Comparisons With Two Empirical Models - Iri-2020 And Nequick-2, Nimalan Swarnalingam, Dong L. Wu, Dieter Bilitza, Daniel J. Emmons, Cornelius Csar Jude H. Salinas, Artem Smirnov, Yenca Migoya-Oru

Faculty Publications

An optimal estimation (OE) technique has recently been developed for F region electron density (Ne) using Global Navigation Satellite System (GNSS) limb sounding on low Earth orbit (LEO) satellites (COSMIC-2, Spire, and FengYun-3). This method provides unprecedented spatiotemporal sampling for global monthly Ne climatology within 100–500 km in 2 hr intervals. The global dataset, collected during mid to moderately high solar activity, is compared with leading models: IRI-2020 and NeQuick-2. Diurnal variations in summer, winter, and equinoctial months are examined for the F2-layer peak, as well as the topside and bottomside of the F region. The observed and modeled NmF2 …

Ibn Al-Haytham (Alhazen), Mithra H. Pirooz, Jonathan B. Santo

Essays in Developmental Psychology

Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haytham was an Arab Muslim born around 965 CE and died circa 1040 CE in current-day Iraq.  A scientist, astronomer, philosopher, and mathematician, he is particularly known for his work in astronomy, mathematics, visual perception, and optics.  In medieval Europe, he was referred to as the “Second Ptolemy”.  As the first to determine that vision results from light being reflected from an object to the eye, he is often referred to as “the father of optics”.  He is also praised for being among the first theoretical physicists.  He was one of the first scientists …

Extraterrestrial - Why They're Almost Certainly Out There, Marcus Brown

2025 Student Academic Showcase

This was an essay I did for my English Composition II class. It’s evaluating an argument from a TED talk of my choice. The TED talk I chose for this writing project was "Extraterrestrial’s - Why They’re Almost Certainly Out There” by Chris Crowe talking about the many exoplanets out there in our universe and beyond. The presentation explains the different sizes, the atmosphere, and the number of exoplanets capable of hosting life. The statistics were used in this analysis like the amount of hydrogen dioxide on each exoplanet. I had to determine if Chris Crowe did a good job …

There's A Method To This Physics Madness, Hanna J. Ross

Physics and Astronomy Presentations

Physics tends to be seen by the general public as scary and unattainable, especially for students who are non-STEM majors. However, at Ursinus College (as well as many other institutions) the professors employ the use of specific problem-solving strategy instruction to mitigate these fears and further general problem solving skills. This study reviews previous experiments evaluating the merit of this strategy and analyzes its results as it relates to Physics on Screen, a physics class at Ursinus geared specifically towards non-majors.

Search For Continuous Gravitational Waves From Known Pulsars In The First Part Of The Fourth Ligo-Virgo-Kagra Observing Run, A. G. Abac, R. Abbott, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Continuous gravitational waves (CWs) emission from neutron stars carries information about their internal structure and equation of state, and it can provide tests of general relativity. We present a search for CWs from a set of 45 known pulsars in the first part of the fourth LIGO–Virgo–KAGRA observing run, known as O4a. We conducted a targeted search for each pulsar using three independent analysis methods considering single-harmonic and dual-harmonic emission models. We find no evidence of a CW signal in O4a data for both models and set upper limits on the signal amplitude and on the ellipticity, which quantifies the …

Rings Of Ice, Erik Johnson

Natural Science Faculty

Have you ever seen the Milky Way? For most Americans, it is impossible to see the band of light from the galaxy outside their homes. To be able to experience the night sky as our ancestors did, we have to travel to places away from light pollution. International Dark Sky Week, which is happening April 22–30 this year, celebrates the night sky and offers everyone a chance to reflect on the lighting choices made around their home and in their community.

Detection And Parameter Estimation Of Supermassive Black Hole Ringdown Signals Using A Pulsar Timing Array, Xuan Tao, Yan Wang, Soumya D. Mohanty

Physics & Astronomy Faculty Publications

Gravitational wave (GW) searches using pulsar timing arrays (PTAs) are commonly assumed to be limited to a GW frequency of ≲4 ×10−7  Hz given by the Nyquist rate associated with the average observational cadence of 2 weeks for a single pulsar. However, by taking advantage of asynchronous observations of multiple pulsars, a PTA can detect GW signals at higher frequencies. This allows a sufficiently large PTA to detect and characterize the ringdown signals emitted following the merger of supermassive binary black holes (SMBBHs), leading to stringent tests of the no-hair theorem in the mass range of such systems. Such large-scale …

Statistical Study Of Solar Wind Conditions Prior To Substorm Onsets, Luke H. Francis

Doctoral Dissertations and Master's Theses

Due to complex, multi-region, coupled plasma systems, auroral substorm onsets have been historically difficult to predict. The northward turning of the interplanetary magnetic field was considered the primary candidate as an external triggering mechanism for substorm onsets. However, that was later shown to be coincidental in nature. This study is motivated by recent multi-spacecraft observations that show how several magnetosheath jets at the bow shock were heavily correlated to substorm onsets, indicated by a strongly radial IMF interval. In the past, studies have looked at small samples of substorms in order to make large-scale predictions. However in this study, a …

Ligo Detector Characterization In The First Half Of The Fourth Observing Run, S. Soni, B. K. Berger, D. Davis, F. Di Renzo, A. Effler, T. Ferreira, E. Goetz, Francisco Llamas Villarreal, Volker Quetschke, J. Glanzer

Physics & Astronomy Faculty Publications

Progress in gravitational-wave (GW) astronomy depends upon having sensitive detectors with good data quality. Since the end of the Laser Interferometer Gravitational-Wave Observatory-Virgo-KAGRA third Observing run in March 2020, detector-characterization efforts have lead to increased sensitivity of the detectors, swifter validation of GW candidates and improved tools used for data-quality products. In this article, we discuss these efforts in detail and their impact on our ability to detect and study GWs. These include the multiple instrumental investigations that led to reduction in transient noise, along with the work to improve software tools used to examine the detectors data-quality. We end …

Ionospheric Evidence Of Lobe Reconnection For Northward Imf, Dora Csonge, Gerard Fasel, John Mann, Audrey Daucher, Owen Bradley, Aidan Hulbert, Thomas Lewer, Sun-Hee Lee, F. Sigernes, D. Lorentzen

Seaver College Research And Scholarly Achievement Symposium

It is believed that magnetic reconnection is one of the main mechanisms to transfer energy and momentum from the for the solar wind into the terrestrial environment. Dungey suggested that magnetic reconnection occurs on the dayside magnetosphere when the interplanetary magnetic field (IMF) is southward. Poleward moving auroral forms (PMAFs) have been identified in past studies as Ionospheric signatures of magnetic reconnection on the dayside.

However, magnetic reconnection can also occur for other geometrical orientations of the IMF. This presentation presents possible examples, 1 December 2021, for lobe reconnection during periods when the IMF x-component is negative, coupled with a …

Dayside Auroral Oval Expansion, Magnetic Flux Erosion, And Substorms, Dora Csonge, Parker Para, Gerard Fasel, Owen Bradley, Gasia Excel, Makena Swenski, Rachel Rodriguez, Sun-Hee Lee, John Mann, F. Sigernes, D. Lorentzen

Seaver College Research And Scholarly Achievement Symposium

Magnetic flux is eroded from the dayside magnetosphere when the interplanetary magnetic field (IMF) turns southward. During this period, the dayside auroral oval shifts equatorward as magnetic flux is transported anti-sunward to the magnetotail. Poleward-Moving Auroral Forms (PMAFs) are thought to be the ionospheric footprints of the flux tubes which are formed and transported tailward. Afterwards, magnetic reconnection occurs in the magnetotail, resulting in a substorm.

This study looks at the time between the onset of dayside magnetic reconnection and the onset of a substorm. Rates of dayside auroral oval equatorward shifts after southward turnings of the IMF are presented, …

Dayside North-South Aligned Auroral Arcs, Taiel Ramirez, Gerard J. Fasel, Wyatt Farrar, Mason Woolfolk, Andrea Black, Cullen Diggs, Clay Shin, Jordan Chiu, Sun-Hee Lee, John Mann, Fred Sigernes, Dag A. Lorentzen

Seaver College Research And Scholarly Achievement Symposium

Observations of North-South auroral arcs (or Sun-aligned) have been recorded for many years. Discrete North-South auroral arcs are located between 73-84° MLAT and are usually associated moderate auroral activity, low solar wind dynamic pressure, and a small IMF z-component. Some observations reported quasi-periodic poleward motions of North-South aligned dayside auroral arcs. This current statistical study contains nine years of All-Sky Camera images obtained from the Boreal Aurora Camera Constellation (BACC) from the Kjell Henriksen Observatory (KHO) in Longyearbyen, Svalbard (GEO: 78.148 N, 16.043 E; AACGM: 75.24 N, 111.21 E). The characteristics of discrete North-South dayside auroral arcs, including spatial and …

The Jwst Early Release Science Program For Direct Observations Of Exoplanetary Systems. Iii. Aperture Masking Interferometric Observations Of The Star Hip 65426 At 3.8 Μm, Shrishmoy Ray, Steph Sallum, Sasha Hinkley, Anand Sivaramkrishnan, Rachel Cooper, Jens Kammerer, Alexandra Z. Greebaum, Deeparshi Thatte, Tomas Stolker, Cecilia Lazzoni, Andrei Tokovinin, Matthew De Furio, Samuel Factor, Michael Meyer, Jordan M. Stone, Aarynn Carter, Beth Biller, Andrew Skemer, Genaro Suárez, Jarron M. Leisenring, Marshall D. Perrin, Adam L. Kraus, Olivier Absil, William O. Balmer, Anthony Boccaletti, Mariangela Bonavita, Mickael Bonnefoy, Mark Booth, Brendan P. Bowler, Zackery W. Briesemeister, Marta L. Bryan, Per Calissendorff

Astronomy: Faculty Publications

We present aperture masking interferometry (AMI) observations of the star HIP 65426 at 3.8 μm, as part of the JWST Direct Imaging Early Release Science program, obtained using the Near Infrared Imager and Slitless Spectrograph instrument. This mode provides access to very small inner working angles (even separations slightly below the Michelson limit of 0.5λ/D for an interferometer), which are inaccessible with the classical inner working angles of the JWST coronagraphs. When combined with JWST’s unprecedented infrared sensitivity, this mode has the potential to probe a new portion of parameter space across a wide array of astronomical observations. Using this …

Utilizing Machine Learning To Predict The Charge Storage Capability Of Lithium-Ion Battery Materials, Manoj Chhetri, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

With the increasing demand for high-performance batteries in applications such as electric vehicles and portable electronics, accurately predicting the charge storage capacity of battery materials is crucial for developing more efficient and reliable energy storage systems. Machine Learning (ML) and data-driven approaches, plays a vital role in enhancing our understanding of Li-ion battery performance, guiding materials design, optimizing system efficiency, and accelerating innovation in energy storage technologies. In this study, an ML-based approach was applied to a dataset of 2345 rechargeable Li-ion battery materials, obtained from the Materials Project online portal, to predict gravimetric charge storage capacity ─ a key …

Three New 2+2 Quadruple Systems With Changing Inclination, Petr Zasche, Z. Henzl, M. Mašek, Jan Kára, H. Kučáková, J Merc, R. Uhlař

Physics & Astronomy Faculty Publications

We present a unique discovery of three new detected systems showing two different phenomena together. These are 2+2 quadruple stellar systems showing two eclipsing binaries as the inner pairs. And besides that, these systems were also found to exhibit the precession of the inner orbits causing the inclination changes manifesting themselves through the eclipse depth variations. We are not aware of any similar known system on the sky nowadays, hence our discovery is really unique. In particular these systems are: CzeV4315 = HD 228777 (periods 6.7391 and 0.91932 d, inclination change of pair B of about 1.4∘ yr−1); ASASSN-V J075203.23−323102.7 …

On Mach's Principle In General Relativistic Cosmological Models, Zach Zito

Student Research Symposium

General Relativity

1. Gravity is the mechanism by which matter influences inertia
2. This influence happens across a spacelike hypersurface
3. Geometrodynamic equations mathematically describe this influence

How It Will End: Physical And Philosophical Implications Of The Fate Of Our Universe, Alex Bittle '26

Honor Scholar Theses

What does physics have to say about the end of our universe? And what does it mean for us, if anything? Answering these questions requires an understanding of the so-called "lambda-cold dark matter" (ΛCDM) model of cosmology, which models the universe as containing an expanding pressure, Λ or dark energy, in a battle with the gravitational attraction provided by dark and regular matter. First, the physics (including observations and theory) of the ΛCDM, including the Big Bang and CMB, the inflationary period, and equations that govern the way the size of the universe changes with respect to time for different …

Parameter Estimation Of Binary Black Hole Coalescence Using Lstm Neural Networks, Lane Scheel

Undergraduate Honors Papers

The Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO) made its first detection of gravitational waves in 2015. Since then, the rate of event detection has only increased, with a detection being made every 2-3 days during the current observing run, O4. This rapid influx of data has the potential to create bottle-necks in data analysis efforts, and can delay the scientific progress which require those efforts. Traditional gravitational wave data analysis techniques, such as matched filtering, require extremely large template banks of synthetic gravitational waveforms and can often fail to provide meaningful limits on system parameters. Not only is this …

Computational Modeling Of Astrophysical Systems, Leleya Iris Stallard

Spring Showcase for Research and Creative Inquiry

This research project focuses on the computational modeling of astrophysical systems using Femap with NX Nastran. The goal was to simulate and analyze the vibrational behavior and structural deformation of celestial bodies under different material compositions and collision conditions. Materials such as iron, granite, titanium, and models for white dwarf stars were used to investigate how varying physical properties affect the systems' dynamic responses. Both isotropic and anisotropic models were created to represent realistic astrophysical materials. Through static and modal analyses, the study explored how internal structure and material stiffness influence the reaction of celestial objects to applied forces and …

19ne Excited States In Explosive Nucleosynthesis, Khang Pham

LSU Doctoral Dissertations

Classical novae and Type I X-ray bursts are stellar explosions that occur in binary systems, where nuclear reactions involving ¹⁹Ne play a crucial role in nucleosynthesis. In novae, the destruction of ¹⁸F via the ¹⁸F(p,alpha)¹⁵O reaction significantly affects the amount of ¹⁸F remaining in the ejecta, directly influencing the detectability of predicted 511-keV gamma rays. However, discrepancies between observed and predicted ¹⁸F abundances highlight uncertainties in the reaction rates, primarily due to unknown properties of resonances in the compound nucleus ¹⁹Ne. In Type I X-ray bursts, the ¹⁵O(alpha,gamma)¹⁹Ne reaction …