Astrophysics and Astronomy Commons^™

Using Moment Maps To Observe Hydrogen Gas In Markarian 54, Amaya Terry

Scholarly Horizons: University of Minnesota, Morris Undergraduate Journal

Hydrogen gas is useful when trying to understand galaxies because it helps make stars. In space, hydrogen gas is in many cases in a form called neutral hydrogen (HI). This gas emits a faint type of light called the 21 cm line, which is a type of radio wave. This light is useful because it can go through dust in space, unlike optical light. This means we can use it to look inside galaxies and study the gas even if there is dust that is in front of stars in the galaxy.

In my research I was given data from …

Survey Of Possible Magnetic Field Sources Around The Intragroup Medium Of Ngc 2563, Edward A. Wallace, Anna Williams

Macalester Journal of Physics and Astronomy

The origin and evolution of magnetic fields in space is an ongoing mystery in astronomy. Previous work has concluded the existence of magnetic fields in galaxy clusters, and to build an evolutionary model, the motivation behind this project is to determine how these magnetic fields form. In order to answer this question, we want to search for magnetic fields in galaxy group NGC 2563. To do this, our project determines the contribution to observed rotation measures of the galaxy group that come from the Milky Way and from the sources themselves.

Modelling Of The Overcontact Eclipsing Binary V826 Aur, Kalev T. Murray-Rouse, John M. Cannon, Anna Williams, Wes Tobin

Macalester Journal of Physics and Astronomy

We present a model of the eclipsing binary system V826 Aur using differential photometric data from the Robert L. Mutel Telescope (RLMT) at the Winer Observatory in Sonoita, Arizona. The calculated time of superconjunction was found to be 60648.7658534 and the period was 0.361701 d. These values were used to generate a best-fit model of the eclipsing binary with the PHOEBE program. The best-fit modelled parameters were found to be: mass ratio (𝑞) is equal to 2.769, the inclination (𝑖) is equal to 80.45◦, the fillout factor (𝑓) equals 0.0961, and the temperature ratio (𝑇2∕𝑇1) is 0.9740. Although not statistically …

Finding High Mass X-Ray Binaries In Ngc 3109, Caeden Miller, John (Jay) Gallagher Iii

Macalester Journal of Physics and Astronomy

High Mass X-Ray Binary systems can be difficult to find in the Milky Way due to high metallicity contributing to mass loss due to stellar wind, so we turn our attention to the galaxy NGC 3109 in order to find these systems. Using archival data from the Hubble Space Telescope using the Wide Field Camera 3, we do photometry in both the F475W and F814W filters for the two fields of view that cover the galaxy. We then plot these magnitudes on a color-magnitude diagram and use isochrones of 5 and 10 million years to gather minimum mass estimates of …

Making And Breaking Chaos: Analog Computer Implementation Of The Lorenz Model, Reed Lefevre, James Doyle

Macalester Journal of Physics and Astronomy

Hybrid analogue-digital computers have been shown to have certain advantages over traditional digital computers when solving nonlinear partial differential equations. Motivated by this fact, we implement the Lorenz equations on an analogue electronic computer and vary the parameters to analyze the bifurcations. With the working circuit, we compared experimental results to various digital simulations to assess the effectiveness of our circuit. We find clear qualitative agreement between the physical circuit and digital simulations; however, we observe a noticeable quantitative difference in behavior. The circuit depicts a picturesque Lorenz Butterfly plot and bifurcates into fixed points and chaos; however, these bifurcations …

Non-Destructive Compositional Analysis Of Lead Halide Perovskite Films Using Thz Spectroscopy And A Three-Oscillator Dielectric Model, Isaac J.C Kisker

Macalester Journal of Physics and Astronomy

Terahertz (THz) Spectroscopy offers a novel approach to probing low-energy phonon excitation in complex crystalline materials like methylammonium lead iodide (MAPI) perovskite films. In this research, we use time-resolved Terahertz Spectroscopy in tandem with a three-oscillator model to non-destructively ascertain the relative volumetric composition of MAPI and residual lead iodide (PbI₂) in spin-coated films. The dielectric function is modeled as a product over longitudinal and transverse optical phonon modes. This model is then fitted to the measured THz spectra, allowing us to extract the contributions from both MAPI and PbI₂.

Examining Mulit-Wavelength Variability And Magnetic Interactions In The Polar St Lmi, Cain Rinkoski

Macalester Journal of Physics and Astronomy

Cataclysmic variable (CV) stars are interacting binary systems that exhibit exotic, multi-wavelength behavior driven by mass transfer from a donor star onto a white dwarf. As rich laboratories for accretion physics, binary dynamics, and the origins of Type Ia supernovae, CVs have been well studied in the X-ray, ultraviolet, optical, and infrared—but remain comparatively underexplored in the radio regime. This paper presents simultaneous, time-resolved optical and radio observations of the magnetic CV ST LMi, aimed at constraining its emission mechanisms and orbital modulation.
The optical light curves display brightness variations of approximately 1.31 ± 0.02 magnitudes on a period of …

A Thermal Control System For The Atlas Hgtd Module Construction Process, Keelin B. Murphy

Macalester Journal of Physics and Astronomy

In the aim of simplifying the production process of 2000 HGTD (High Granularity Timing Detector) modules at IJClab for the high luminosity phase of the ATLAS experiment at the CERN Large Hadron Collider, I designed, coded, and constructed an automatic temperature control system for module assembly and testing. To this end, I examined the module’s thermal response to changes in air temperature using a climate chamber and to various currents fed through a Peltier device situated under the module. I adapted the Peltier setup into a fully independent control system driven by an Arduino microcontroller running a PID feedback loop.

Dose Characterization Of Galactic Cosmic Rays In The Human Brain: A Phits-Based Study With A Segmented Anatomical Phantom, Shanice N. Manning

LSU Master's Theses

Astronauts aboard the International Space Station (ISS) are chronically exposed to a complex space radiation environment composed of galactic cosmic rays (GCR), solar particles, and Earth's trapped radiation. These high-energy particles interact with spacecraft shielding, producing secondary particles that can penetrate inside and deposit energy in sensitive tissues. Although animal studies have been useful in assessing space radiation risks, anatomical and physiological differences limit their applicability to human anatomy especially neuroanatomy. To address this gap, we developed a computational framework to model radiation dose distribution within the human brain using Monte Carlo simulations in Particle and Heavy Ion Transport code …

Making Observations, Erik Johnson

Natural Science Faculty

After years of planning and construction, the NSF-DOE Vera C. Rubin Observatory has collected its "first light" from space, and the first images have been released to the public.

The Search For Magnetar Giant Flares In Archival Gamma-Ray Burst Data To Constrain Their Rates And Energetics, Aaron Trigg

LSU Doctoral Dissertations

Magnetar giant flares are rare, extremely bright bursts of gamma-rays from highly magnetized neutron stars. These events are difficult to identify because, at extragalactic distances, they can appear similar to other astrophysical phenomena. Only a handful have been confidently identified to date, limiting our understanding of their origin and physical properties. This dissertation focuses on expanding the sample of known events and enabling a more detailed characterization of their observational features. We report on two newly identified examples, GRB 180128A and GRB 231115A, that are consistent with a magnetar origin based on their spectral properties and association with nearby star-forming …

Can We Discover Physical Models Using Machine Learning? A Case Study Of Galaxy Sizes, Festa Buçinca-Çupallari, Ariyeh Maller, Viviana Acquaviva, Austen Gabrielpillai, Rachel S. Somerville

Publications and Research

We explore the ability of machine learning methods to discover underlying equations of physics by searching for the equations governing galaxy size in a semianalytic model. This case study allows us to evaluate the process as we know the ground truth. We find that we fail to find an equation to predict galaxy size on the entire data set, but are successful when we separate out disk galaxies where we expect the physics driving galaxy size to be different than in bulge-dominated systems. We are also able to find an equation for bulge size, but not without adding an additional …

Large Bandgap Observed On The Surfaces Of Euzn2As2 Single Crystals, Dejia Kong, Siavash Karbasizadeh, Ganesh Narasimha, Paras Regmi, Chenggang Tao, Chenggang Tao, Sai Mu, Rama Vasudevan, Ian Harrison, Rongying Jin, Zheng Gai

Faculty Publications

EuZn₂As₂ (M = Zn, Cd, In, Sn etc.) is an excellent material system for studying magnetism-tuned topological properties. However, discrepancies exist between experimental data and theoretical calculations regarding the bulk and surface bandgaps. In this work, cleaved EuZn₂As₂ crystals are studied using scanning tunneling microscopy/spectroscopy and density functional theory calculations. Triangular-shaped defect-induced modifications in the local density of states help distinguish between Eu-terminated and AsZn-terminated surfaces. While large bandgaps ( ~1.5 eV at 77 K) are observed on both pristine surfaces, the bandgap size is found to be highly sensitive to local heterogeneity, tending …

A Wide-Field Map Of Ultracompact Dwarfs In The Coma Cluster, Richard T. Pomeroy, Juan P. Madrid, Conor R. O’Neill, Alexander T. Gagliano

Physics & Astronomy Faculty Publications

A data set of 23,351 globular clusters (GCs) and ultracompact dwarfs (UCDs) in the Coma cluster of galaxies was built using Hubble Space Telescope Advanced Camera for Surveys data. Based on the standard magnitude cut of MV ≤ −11, a total of 523 UCD candidates are found within this data set of compact stellar systems (CSS). From a color–magnitude diagram analysis built using this catalog, we find a clear mass–magnitude relation extending marginally into the UCD parameter space. The luminosity function defined by this data set shows an excess of sources at bright magnitudes, suggesting a bimodal formation scenario …

Electroexcitation Of Nucleon Resonances And Emergence Of Hadron Mass, Patrick Achenbach, Daniel S. Carman, Ralf Gothe, Kyungseon Joo, Victor I. Mokeev, Craig D. Roberts

Faculty Publications

Developing an understanding of phenomena driven by the emergence of hadron mass (EHM) is one of the most challenging problems in the Standard Model. This discussion focuses on the impact of results on nucleon resonance (N*) electroexcitation amplitudes (or γ_vpN*) obtained from experiments during the 6 GeV era in Hall B at Jefferson Lab on understanding EHM. Analyzed using continuum Schwinger function methods (CSMs), these results have revealed new pathways for the elucidation of EHM. A good description of the Δ (1232) 3/2⁺, N (1440) 1/2⁺, and Δ (1600) 3/2^{+ …}

Investigating Long-Lasting Meteor Train Phenomena In Optical And Radio Regimes, Logan E. Cordonnier

Physics & Astronomy ETDs

Throughout history, meteors have been regarded as fascinating and portentous events, with bygone astronomers diligently recording their occurrence. The research presented herein continues in this tradition, using modern instruments, software, and data reduction techniques to study long-lasting meteor trail phenomena, specifically in the optical (persistent trains; PTs) and radio (meteor radio afterglows; MRAs) regimes. The overarching goal was to investigate the similarities between these phenomena, which began with the creation of a PT catalog. Many of the prior assumptions about the nature of PTs were found to be unsubstantiated, and several new behaviors were uncovered. This includes the discovery of …

Detecting Ionospheric Disturbances Using High Frequency Coastal Radar Transmissions From The West Coast Of The United States, Riley N. Troyer, Kenneth Obenberger, Michael Negale, Eugene Dao, Zsolt Balint, Eric Burnside, Kris Robinson, Jeffrey M. Holmes, Pavel Inchin, Jonathan Snively

Space Dynamics Laboratory Publications

Coastal radar system are located around the world and many happen to transmit at frequencies capable of skywave propagation via the ionosphere. Therefore, they can be detected hundreds to thousands of kilometers away. This paper demonstrates the opportunity to detect 39 Coastal Ocean Dynamics Application Radar transmitters located on the western coast of the United States using three HF radio receivers in Utah and New Mexico. It also illustrates the possibility to use the phase and Doppler measurements of these signals to derive displacements of the refracting ionospheric layer up to meter resolution for the 2023 annular solar eclipse, an …

Understanding Stellar Element Formation Through Nuclear Reactions, Irena Langer, Mally Panek, Kiyah Young-Wilson, Adam Fritsch

Physics Student Scholarship

Studying nuclear structure has many applications, such as developing a stronger understanding of stellar nucleosynthesis, or how elements are formed inside of stars. Our research focuses on analysis of the proton evaporation nuclear reaction of Carbon-12 on Aluminum-27 in order to extract information about the structure of the nuclei involved. We are studying the cross section, or likelihood, of this reaction, using both experimental and modeled data. Since the cross section of a nuclear reaction depends on the physical characteristics of the nuclei involved, we can use the cross section to analyze our work.

Hot Donors In Cataclysmic Variables: The Case Of Ei Psc, Jan Kára, S. Zharikov, M. Wolf, N. Vaidman, A. Agishev, S. Khokhlov, C. E. Chavez

Physics & Astronomy Faculty Publications

Context. We present results of time-resolved optical spectroscopy and photometry of the short-orbital period dwarf nova EI Psc.

Aims. This study aims to determine fundamental system parameters of EI Psc, study properties of accretion structures in the system, and investigate its origin and current evolution state.

Methods. We analyse newly obtained time-resolved spectroscopic and photometric observations as well as archival data. We used light curve modelling, Doppler tomography, and MESA evolutionary models to study the characteristics of EI Psc.

Results. The system contains a relatively low temperature (T_eff = 6130 K) white dwarf with mass of M …

Auroral Hemispheric Power Asymmetry During Geomagnetic Storms: A Multi-Database Investigation Using Ae And Supermag Indices, Melvin J. Reyes Lozada

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Engineering at Morehead State University in partial fulfillment of the requirements for the Degree Master of Science by Melvin J. Reyes Lozada on June 20, 2025.

Uncovering Multiscale Structure-Property Correlations Via Active Learning In Scanning Tunneling Microscopy, Ganesh Narasimha, Deja Kong, Paras Regmi, Rongying Jin, Zheng Gai, Rama Vasudevan, Maxim Ziatdinov

Faculty Publications

Atomic arrangements and local sub-structures fundamentally influence emergent material functionalities. These structures are conventionally probed using spatially resolved studies and the property correlations are deciphered by a researcher based on sequential explorations, thereby limiting the efficiency and scope. Here we demonstrate a multi-scale Bayesian deep-learning based framework that automatically correlates material structure with its electronic properties using scanning tunneling microscopy (STM) measurements in real-time. Its predictions are used to autonomously direct exploration toward regions of the sample that optimize a given material property. This method is deployed on a low-temperature ultra-high vacuum STM to understand the structure-property relationship in a …

Exploring The Very Early Cosmological History With Dark Matter And Primordial Black Holes, Phuc Duc Loc Ngo

Physics & Astronomy ETDs

We explore the possibilities of nonstandard early cosmological histories and their potential roles to explain DM. We study how particle DM is produced with scenarios of early matter domination (EMD), how primordial black holes (PBHs), which could also be a DM candidate in certain mass ranges, are formed with enhanced curvature perturbation or FOPT and the corresponding gravitational wave (GW) signals, how PBHs could increase their mass by accretion during EMD and the corresponding GW signals.

Study Of Agn Jet And Possible Connection Among Different Agn Classes, Shahjahan Iqbal

University Departments

No abstract provided.

Spin Precession In Magnetized Kerr Spacetime, Karthik Krishnamurthy Iyer

University Departments

No abstract provided.

Interacting Galaxy Clusters As A Probe To Cosmic Filaments, Shreya R. Kamath

University Departments

No abstract provided.

Photometric And Spectroscopic Properties Of Hydrogen-Rich Supernovae, Chaitrika B. M

University Departments

No abstract provided.

Probing Dust Grain Optical Properties In The Ism Using Diffuse Ultraviolet Observations Together With Radiative Transfer Modelling, Nilanjana Dey Choudhury

University Departments

No abstract provided.

Higher-Order Exceptional Points In A Non-Reciprocal Waveguide Beam Splitter, Hamed Ghaemidizicheh, Shahram Dehdashti, Andreas Hanke, Ahmed Touhami, Janis Nötzel

Physics & Astronomy Faculty Publications

Non-Hermitian systems have attracted significant interest because of their intriguing properties, including exceptional points (EPs), where eigenvalues and the corresponding eigenstates coalesce. In particular, quantum systems with EPs exhibit an enhanced sensitivity to external perturbations, which increases with the order of the EP. Therefore, higher-order EPs hold significant potential for advanced sensing applications, but they are challenging to achieve due to stringent symmetry requirements. In this work, we study the dynamics of a generalized lossy waveguide beam splitter with asymmetric coupling by introducing non-reciprocity as a tunable parameter to achieve higher-order EPs even without dissipation. Moreover, we analyze the evolution …

Data Sonification: The Art Of Exploring Space Through Sound, Jessica Cotturone

Music: Student Scholarship & Creative Works

Data sonification is a cutting-edge, interdisciplinary field that involves the transformation of data into sound. As the amount of data collected in today’s world continues to rise exponentially, new collaborations between scientists, mathematicians, and musicians are exploring the potential applications of sonification. Turning data into sound can create new avenues for interpretation and can increase accessibility for visually-impaired populations. The sonic renderings produced by this practice exist on a spectrum from sound to music and vary in their levels of objectivity and expressivity. One of the major areas where data sonification is providing a new scientific and artistic perspective is …

Temperature, Albedo, And Emissivity Of Triton And Proteus From Voyager 2 Iris Data, Garrett Nobis, Vincent Chevrier

Space and Planetary Science Faculty Publications and Presentations

The Voyager 2 infrared interferometer and spectrometer (IRIS) spectra for Triton are revisited, and the Proteus IRIS spectra are looked at for the first time. Fifty more spectra are added to the average of 16 previously used for Triton. The unit emissivity Planck function temperature result is 37.9  ±  0.5 K. Iterating IRIS temperatures over several emissivities allows for constraints on emissivity and Bond albedo based on past data. Upper and lower bounds on Triton’s temperature and albedo of 37.9  ±  0.5 to 46.1  ±  0.7 K for temperature and 0.67−0.86 for albedo are determined from the IRIS data and …