1. Dissociative Electron Attachment to Ethanol
Aysia Bittinger, University of North Georgia
Dissociative electron attachment (DEA) is a key process by which low-energy electrons (1 to 15 eV) cause significant damage to DNA. To understand DEA to a complex arrangement of biomolecules like DNA, we must first understand DEA to simple, individual molecules. This project studies DEA to the simple alcohol, ethanol, because of its medical and clean energy applications. A comparison is made between experimental resonance energies and theoretical fragmentation pathways with corresponding thermodynamic thresholds to understand the mechanisms behind DEA to ethanol. This comparison yielded results similar to other studies regarding the OH- fragment. However, results regarding the remaining fragments were less consistent with other literature. Further research into these discrepancies is required to discover the most accurate resonance energies of these fragments.
2. Chaotic dripping in an electro-coflow setting
Lexi Dowdy, Augusta University
Drops formed in a dripping regime usually present monodispersity in size when generated at low flow rates. At higher flow rates, the periodic character of the process is lost, and it exhibits chaotic behavior, affecting the size of the drop, and the frequency of formation. In this work, we study the generation of emulsion drops in glass-based microfluidic devices. The emulsion drops formed in a coflow setting showed different routes to chaos, period-doubling and intermittencies, depending on the properties of the used fluids. In an electro-coflow setting, we studied how this non-periodic behavior affects the transition from the dripping regime to the microdripping one.
3. Finding Hidden Galaxies at High Redshift with JWST: Red F150W-Dropout Galaxies in the COSMOS-Web Survey
Elaine Gammon, University of Georgia
For decades dusty star-forming galaxies (DSFGs), especially those in the early universe, have evaded our detection at ultraviolet and optical wavelengths. Approximately 30% of all high redshift DSFGs lack optical counterparts. Leveraging the extreme sensitivity of JWST, we have uncovered a population of high redshift galaxies that are heavily attenuated at rest-frame optical wavelengths. To better understand their volume density and physical properties at early cosmic times we look at galaxies that have an estimated redshift of 4<z<6 and likely exhibit substantial dust obscuration. We utilize data from the COSMOS-Web survey, a NIRCam (1.1-4.4 µm) and MIRI (7.7 µm) imaging program of the COSMOS extragalactic legacy field using JWST. We select galaxies with F277W-F444W > 0.5 that have photometric redshifts 4<z<6 and no detection in the F150W filter. The resulting sample includes 309 galaxies, with an average redshift of 5.3, an average stellar mass of ~9 (log(mass / Msun)), an average star-formation rate of ~10 (SFR / Msun per yr), and an average dust attenuation of A_V = 1.2. The investigation of high redshift DSFGs will be crucial to better understanding galaxy evolution in the early universe, because current models of early galaxy evolution are purely based on optical and ultraviolet observations, and galaxies in the early Universe might be dustier than previously supposed.
4. Distant Galaxy Cluster Survey
Nadia Hansen, University of Florida
We created a cluster catalog based on multiple sky surveys and are currently cross-matching spectroscopic data from DESI Early Data Release (Dark Energy Spectroscopic Instrument) to determine redshifts for ~1,000 galaxy clusters.
5. Gamma Ray Bursts: Exploring the Universe’s Most Violent Explosions
Shamita Hanumasagar, Georgia Institute of Technology
Gamma Ray Bursts (GRBs) are short but highly energetic bursts of gamma-ray radiation that can stem from many astrophysical phenomena, such as stellar collapse and dense-body mergers. By studying GRBs we gain a greater insight into various extreme events, such as black hole formation, supernovae, and early-universe activity to achieve a more robust understanding of the cosmos’s physical properties. GRBs are often studied individually; however, having a catalogue of many analysed GRBs would prove a useful tool for comparing them to other transients as well as identifying systematic tendencies for GRBs themselves. To create this comprehensive sample for analytical study, our group seeks to investigate numerous GRBs to track their physical parameters and view them against standard literature. One such GRB is GRB 061121, from November 21st 2006. By examining the flux density of GRB 061121 as it relates to time and frequency, we can conclude information about its features, such as its evidence of a reverse shock and plateau in the X-ray data. This information, alongside many other GRBs, will be used in our collective sample to construct a more panoptic view of GRBs and their general characteristics.
6. Time-Frequency Analysis of Gravitational Waves with the Continuous Wavelet Transform
Alice Heranval, Georgia Institute of Technology
When compact astrophysical objects such as black holes or neutron stars spiral toward one another and merge, they emit gravitational waves detectable by observatories like LIGO and Virgo. This poster outlines the application of the Continuous Wavelet Transform (CWT) for gravitational wave signal analysis by generating maps of the time-frequency structure of the signal. We demonstrate CWT’s effectiveness across events from the first three gravitational wave transient catalogs, showcasing its flexibility in creating time-frequency maps and how varying CWT parameters impacts the result.
7. Two Candidates for Dual AGN in Dwarf-Dwarf Galaxy Mergers
Olivia Holmes, University of Alabama
Dual AGN are important for understanding galaxy-merger-triggered fueling of black holes and hierarchical growth of structures. The least explored type of dual AGN are those associated with mergers of two dwarf galaxies. According to observations and cosmological simulations, dwarf galaxies are the most abundant type of galaxies in the early Universe and the galaxy merger rate is dominated by dwarfs. However, these mergers are generally too distant to be directly observed, and low-redshift dwarf-dwarf merger-related dual AGN are notoriously hard to find. In this paper, we present the first results of our large-scale search for this elusive type of object and the first two candidates for dual AGN in dwarf-dwarf mergers. Both objects exhibit tidal features (tails and bridges) characteristic of galaxy mergers/interactions. One object is apparently in a late-stage merger with an AGN separation of < 5kpc, while the second is in an early-stage merger with interacting galaxies having established a tidal bridge. Both objects have dual, luminous X-ray sources that are most likely due to actively accreting massive black holes. Also, both objects have infrared counterparts, with colors consistent with being AGN. Follow-up observations will provide us a glimpse into key processes that govern the earliest phases of growth of galaxies, their central black holes, and merger-induced star formation.
8. The Impact of Nebular Line Emission on SED-Derived Galaxy Properties
Grace Krahm, Agnes Scott College
Spectral energy distribution (SED) modeling is commonly used in observational studied to estimate the stellar mass of a galaxy. However, this method relies on several sets of a assumptions in the radiative transfer process such as the galaxy’s star formation history and its impacts on the dust and gas in the galaxy. Nebular line emission from the HII regions around young stars can be an unexpected source of detected flux from the galaxy which impacts the SED modeling. Observationally detecting these nebular lines can be very time intensive and often impossible for galaxies that are farther away. In order to quantify the extent of how nebular lines impact estimated stellar masses throughout cosmic time we use galaxies from the SIMBA hydrodynamical simulations.
9. Preparation of Atomically Smooth SrTiO₃ Substrate Surface
Monique Kubovsky, University of Florida
Using Atomic Force Microscopy (AFM), the surface of SrTiO₃ (STO) has been observed and studied. Aside from STO having unique properties, such as superconductivity and quantum paraelectricity, the study of STO is also important because its perovskite structure allows it to be used as a substrate for thin film deposition. To use it as such, the material needs to have an atomically smooth surface with a singly terminated surface that is optimal for a good quality thin film to deposit. SrTiO₃ can have either a TiO₂-terminated surface or an SrO-terminated substrate, which is significant because the termination type determines the order in which the atoms of thin films are deposited on the substrate and the composition and properties of the film. SrTiO₃ having a TiO₂-terminated surface means that only the TiO₂ layer is exposed at the surface. The main aim of this project is the use of an annealing process to produce a TiO2-terminated SrTiO₃ surface that has a terraced structure with steps that are about the same height as the unit cells of the substrate i.e. atomically smooth. This is done using ultrasonic cleaning, thermal annealing, and AFM. Looking forward we will use these substrates for thin film growth using pulsed laser deposition. This project is significant because it focuses on perfecting the two-dimensional interface between the substrate and thin film, which plays an important role in the properties of oxide thin films with implications in oxide electronics, where metal oxides are substituted for traditional silicon.
10. Light-induced Multiply Quantized Vortex States in Dirac-like Materials
Lauren Massaro, Kennesaw State University
Floquet engineering of materials leads to the hybridization of their electronic bands and a concomitant topological phase change. Light, with its multiple degrees of freedom, i.e., polarization, intensity, and frequency, impacts matter through their interaction. Still, additional degrees of freedom can arise from the spatial control of optical beams, and vortex light beams are one such example, as they carry orbital angular momentum in addition to their polarization. This work considers a two-dimensional massive Dirac-like system subjected to a monochromatic vortex light beam. Utilizing Floquet’s theorem, we identify the set of frequencies and polarizations for which total angular momentum is conserved and map the subsequent Floquet Hamiltonian to the Hamiltonian of an s-wave superfluid hosting multiply quantized vortex core states, and this allows us to analytically determine the number of vortex states that appear in our system. From here, we utilize Bessel decomposition to numerically diagonalize the system’s Hamiltonian in the resonant regime in order to present a complete description of the photon-dressed electronic vortex states that emerge from this irradiated system in terms of their angular momentum-dependent dispersion relation and real-space extension.
11. MEMESat Radio
Delaney Murray, University of Georgia
UGA SSRL’s MEMESat-1 is an amateur radio satellite designed as an educational platform for k-12 students. The satellite was originally designed around an opensource radio which lab members constructed in-house. However, unforeseen technical problems necessitated that we search for a new, off-the-shelf radio solution with similar functionality. As much of the satellite had already been built, requirements for the new radio needed to be established based on the surrounding satellite design and mission criteria. The final tradespace compared 10 radios using subjective and objective scoring methods.
12. Evolution of Disk Angular Momentum in Triaxial Dark Matter Halos
Tara Nester, Georgia Southern University
Galactic halos are believed to form through both the early inflow of dark matter from the cosmic web and mergers over and extended period. At the same time, stellar disks are forming within this evolving halo. How a stellar disk responds to a changing halo is investigated in this study using live n-body disks embedded in an analytic triaxial potential. At triaxialities of a few percent, we find that while there are subtle perturbations in the disk, there is no significant change in the total disk angular momentum. However, between 5 and 10% triaxialities there is a sharp transition to a strong disk tilt. This angular momentum evolution is observed to occur in our models after a delay of about half a Hubble-time.
13. Simulating Interactions with Lunar Rocks
Rinisha Ramprakash, University of Georgia
The moon, like all air-less bodies, is exposed to the harshness of the environment of space. The surface is bombarded by solar wind ions, cosmic rays, Ultraviolet, and X-ray radiation, which interact with the soil in a process referred to as space weathering. Further studies have found that micrometeorite impacts affect the moon’s soil, and by studying micrometeorite interactions, we can learn about the early conditions and processes in the solar system’s history. Knowing about the dynamics of the moon’s regolith leads to a better understanding of the complex mineralogy on the moon. The purpose of this research is to simulate the lunar regolith and explore the dynamics of interacting particles. One of the main constituents of lunar rocks is the mineral forsterite (Mg2SiO4).
14. Nuclear Spectroscopy of Vanadium 52 using the V51(d,p)V52 reaction
Ashley Sandrik, Florida State University
It is an analysis of the nuclear structure of vanadium using the V51(d,p)V52 reaction. Particular attention is given to the L=4 state.
15. A Search for Low States in the Light Curves of 41 Intermediate Polars
Sierra Sanne, University of Florida
We investigate 41 confirmed intermediate polars’ ATLAS and TESS lightcurves for low states, during which they fade unpredictably and for anywhere from days to months. We find that nearly one-fifth of these systems show either definite or possible low states, which we define as a sustained fade of 0.5 magnitudes or more. While some of these low states have been previously reported, many are newly identified. One of these systems, MU Cam, was serendipitously observed by TESS while it started to fade into a low state, one of the first instances there has been TESS data that captured the beginning of a low state in an intermediate polar. Using a 2D power spectrum of the TESS data, we investigate how MU Cam’s mode of accretion changes in response to the reduced mass-transfer rate during that low state. Our results expand upon previous investigations of low states in intermediate polars and serve as the most comprehensive search undertaken for low states in intermediate polars.
16. Searching for Lens Structure in SPT0311-58
Savannah Still, University of Florida
Using James Webb Space Telescope (JWST) NIRCam and MIRI imaging, which we acquired through Program GO 1791 (PI: Spilker), we extract photometry. To calculate photometric redshift, we fit the Spectral Energy Distribution (SED) for the additional structures near the SPT0311-58 system. Current gravitational lens models for this system do not account for structures aside from the central lens, which is magnifying the source at a redshift z=6.900. These auxiliary structures are identifiable through examination of HST and ALMA images of the same region. To improve current lens models, further information is needed about other structures in the system to determine whether they are foreground objects or associated with the lens. In extracting photometry from these objects at each available wavelength, we use GALFIT to model the central lens, which would otherwise contaminate the signal from nearby structures within the data. With these fluxes, we use EAZY-py to calculate respective redshifts through SED fitting. These redshifts will inform whether these structures are important to account for in the lens or not.
17. PEEKing Into the Universe
Kayla Taylor, Florida Institute of Technology
The advancement of imaging technology over the last twenty years has provided astronomers with more ways to view and classify galaxies. The evolution of classification techniques has progressed from manual data interpretation to the application of deep learning models for categorizing astronomical datasets. Using deep learning techniques increases the efficiency of processing astronomical data, and allows for more discovery. This work shows that utilizing deep learning models can accurately and efficiently classify different types of galaxies. While the interpretability of most deep learning models remains a challenge, this study employs Probabilistic Explanations for Entropic Knowledge extraction (PEEK) to analyze the information flow through the model. This not only enhances our ability to effectively classify galaxies but also renders the decision-making process of the deep learning model transparent.
18. Utilizing the Accuracy of TESS Asteroseismology for the Advancement of Stellar Archeology
Artemis Theodoridis, University of Florida
Ever since the emergence of astronomy, astronomers have wanted to understand how our Milky Way formed and assembled. With consistent advancements in technology, there have been a plethora of opportunities to study how our galaxy works in its present state and to analyze how it came to be this way. However, in order to propose theories about our galaxy, astronomers need reliable ages for a multitude of stars. In previous work, I have put together a sample of red giants with spectroscopic compositions and asteroseismic masses. Theoretical modeling is now required to calculate these stellar ages. Previous asteroseismic analyses have been limited to small fields in the sky, which is not optimal for studies related to the entire galaxy. With the new introduction of TESS, an all-sky survey including millions of red giants, and at least 158,000 identified oscillators, limited sky coverage is no longer a great concern (Hon et al. 2021). In the next year, I propose to use a combination of previous and new theoretical stellar evolution models, to create a catalog that consists of ages for ~15,000 stars with a range of compositions and galactic locations. My previous experience building the fundamental dataset on which this theoretical exploration is based will allow me to conduct a deeper analysis of previous and developing models. With this research, we will have a more accurate list of a variety of stars, allowing us to better understand galactic evolution.
19. Characterization the Metallicity Dependence of Terminal Wind Speeds for Wolf-Rayet Stars
Mateo Valera, University of North Georgia
Wolf-Rayet (WR) stars are important for understanding the evolution of massive stars. A major component of this evolutionary significance is their intense wind, which leads to considerable mass loss. Models indicate that the metallicity of WRs affect the strength of their terminal winds. Previous empirical data comparing WR stars in the Large and Small Magellanic Clouds and the Milky Way indicated a relationship between the metallicity and wind strengths of WR stars. However, the analysis assigned the average metallicity of their respective galaxies to all WR stars, ignoring potential differences between stars. Furthermore, precise parallaxes from Gaia produce different mass-loss and luminosity measurements than those previously used. We present a project working toward determining the metallicity and wind strengths of individual WR stars using measurements from Gaia DR3 and ground-based data. A count of 18 WR stars along with comoving F, G, and K type stars will be analyzed using optical, high-resolution, and ground-based spectroscopy to measure the metallicities and terminal wind velocities of the WR stars. This analysis will lead to a better understanding of the causes of the formation of such intense winds.
20. ChatGPT Zero-Shot Performance On Medical Physics of the Radiation Oncology Board Exam
Vanessa Wildmen, Emory University
Zero-shot learning is a form of deep learning where, at test time, the learner observes samples from classes it was not trained on, and must predict what class the sample belongs to. Using machine learning, we have trained ChatGPT on questions of the American College of Radiology In-Training Examination for Radiation Oncology Residents. With this model, the performance of ChatGPT on accurately answering questions from the medical physics portion of the exam was assessed.
21. The Relationship Between Viscosity and Increasing Ampicillin Resistance in E. Coli
Olivia Ziemer, University of Tennessee at Chattanooga
Antibiotic resistance in bacteria has become an increasingly significant issue in modern medicine. Despite the regularity of antibiotic resistance, there is still much we do not yet know about the mechanisms employed by resistant bacteria. One of the mechanisms ampicillin uses to attack E. Coli is to prevent the synthesis of the cell wall. Several studies, using an Atomic Force Microscope, have discovered that the cell walls of E. Coli become stiffer when they are made to be resistant to antibiotics. Here we measure the rheological properties of E. Coli with and without ampicillin in a motility buffer. We hypothesize that the increased stiffness on a cellular level will manifest as a collective property, changing the shear stress, viscosity, and modulus. Our results taken from the rheometer display an increase in viscosity as the bacteria become increasingly resistant to ampicillin.