Physical Sciences and Mathematics Commons^™

Computational And Experimental Data For Undoped And Er-Doped Lithium Tantalate Nanofluorescent Probes, Mkhitar A. Hobosyan, Andrea Pelayo Carvajal, Bhupendra B. Srivastava, Tamanna Zakia, Mohammed Jasim Uddin, Karen S. Martirosyan, Eric Rodriguez, Kofi Nketia Ackaah-Gyasi, Nicholas Dimakis

Physics and Astronomy Faculty Publications and Presentations

The density functional theory (DFT) and experimental data presented in this paper refer to the research article “Computational and experimental study on undoped and Er-doped lithium tantalate nano fluorescent probes”. The DFT data contain electronic and optical properties for both LiTaO3 and LiTaO3:Er+3, with Er+3 occupying either Li or Ta sites at 4.167 mol. %. All these properties were calculated at the generalized gradient approximation (GGA) limit. Additionally, electronic information was calculated using the hybrid functional by Heyd, Scuseria, and Ernzerho (HSE06), which accurately predicts the location in energy for all Er-4f orbitals. We also include simulated X-ray near edge …

Search For Core Collapse Supernovae Signals In Ligo’S Third Observation Run Using A Network Of Gravitational Wave Detectors Integrated With A Multiclass Convolutional Neural Network, Shahrear Khan Faisal, Gaukhar Nurbek, Michael Benjamin, Bhawana Sedhai, Soma Mukherjee

Physics and Astronomy Faculty Publications and Presentations

In the existing body of literature, numerous waveforms of core collapse supernovae (CCSN) have emerged from extensive simulations conducted in high-performance computing facilities globally. These waveforms exhibit distinct characteristics related to their explosion mechanisms, influenced by parameters such as progenitor mass, angular momentum, gravitational wave energy, peak frequency, duration, and equation of state. Core collapse supernovae stand out as highly anticipated sources in LIGO’s fourth observation (O4) run, prompting dedicated efforts to detect them. The integration of machine learning, specifically convolutional neural networks (CNN), has become a pivotal avenue for analysis. This study addresses a fundamental query: how can a …

Exploring The Early Solar System: Cometary Chemical Fingerprints: A Study Of Comet C/2022 E3 (Ztf) Via Near-Infrared Spectroscopy, Grace Puchalski

Undergraduate Research Symposium

Comets are small, icy remnants from the solar system formation (4.5 billion years ago). Their interior composition should reflect the composition and conditions presented in the mid-plane of the protoplanetary region where (and when) they formed. These small objects predominantly reside in two major reservoirs, the Oort cloud and the Kuiper belt. Comets coming from the Oort cloud have long orbital periods while comets from the Kuiper belt have short orbital periods (< 200 years). An overarching goal in astronomy is to understand the conditions presented in the planetary region in the early solar system. Since comets lack a known mechanism of self internal heating, any processes that have changed their composition should only affect a few meters deep, which is believed to be excavated over a course of a perihelion passage into the inner parts of the solar system. As comets get closer to the Sun, solar irradiation causes their ices to sublime, leaving a formation of a freely expanding atmosphere (coma). Depending on the science interest, astrophysicists use different techniques for data collection, a common one being spectroscopy. Using iSHELL spectrograph at the NASA-Near-Infrared Telescope Facility (IRTF), we examine the primary chemical composition (e.g., H2O, CO, CH4, C2H6, C2H2, H2CO, NH3, CH3OH, OCS, and OH) of cometary coma in bright comet C/2022 E3 (ZTF). Our preliminary results indicate the H2O production rate of ~3.4E28 (molecules per second), which corresponds to the rotational temperature of 86 (K). Cometary atmospheres are dense enough that molecules in the inner coma are thermalized by collision (Local Thermodynamic Equilibrium), thus 86 (K) is a physical parameter of coma. We compared the production of the rest of species with that of water (in %) and our results indicated that comet E3 was typical (close to average) in mixing ratios of all volatile species. By mapping the intensity of light with distance from the nucleus,we were able to examine the spatial distribution of volatiles and dust in E3’s coma which were consistent with production directly from the nucleus.

Striatal Beat Frequency Interval Timing Model With Microgravity Stressor, Jason Michael Fitzgerald, Sorinel Oprisan

Journal of the South Carolina Academy of Science

The Striatal Beat Frequency (SBF) model of interval timing uses frontal cortex (FC) neural oscillations to record the state of the brain at the reinforcement time Tc during fixed interval (FI) procedures in the long-term memory (LMEM). The state of the FC oscillators at any given time is stored in a short-term memory (SMEM) buffer. The SBF model uses the spiny neurons of the basal ganglia (BG) as coincidence detectors to produce beats between the content of the SMEM and LMEM. Across multiple species that can perform interval timing, there are two invariant properties: (a) the timing is precise, and …

Toi–757 B: An Eccentric Transiting Mini–Neptune On A 17.5–D Orbit, A Alqasim, N Grieves, N M. Rosário, D Gandolfi, J H. Livingston, S Sousa, K A. Collins, J K. Teske, M Fridlund, Ryan J. Oelkers

Physics and Astronomy Faculty Publications and Presentations

We report the spectroscopic confirmation and fundamental properties of TOI 757 b, a mini Neptune on a 17.5 d orbit transiting a bright star (⁠ mag) discovered by the TESS mission. We acquired high precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of …

From Stars To Moons: Investigating Stellar Rotations, Planetary Interactions, And Exoplanetary Prospects, Rosario Cecilio-Flores-Elie

Dissertations, Theses, and Capstone Projects

The thesis is divided into two key sections. The first chapter presents the results of analyzing TESS light curves for 99 targets within the Carina-Near moving group. By deriving rotational periods, this analysis supports stellar age estimation, contributing to the broader efforts of the Backyard Worlds: Planet 9 citizen project in determining age parameters for 89 newly identified systems, including ultracool dwarf companions. These findings enhance our understanding of stellar rotation and evolution, offering new insights into the development of secondary co-moving objects like brown dwarfs.

The second chapter investigates planet-moon interactions within our solar system by examining mass ratios, …

Optically Targeted Search For Gravitational Waves Emitted By Core-Collapse Supernovae During The Third Observing Run Of Advanced Ligo And Advanced Virgo, Marek J. Szczepańczyk, Yanyan Zheng, Javier M. Antelis, Michael G. Benjamin, Marie-Anne Bizouard, Alejandro Casallas-Lagos, Pablo Cerda-Duran, Derek Davis, Dorota Gondek-Rosinska, Soma Mukherjee

Physics and Astronomy Faculty Publications and Presentations

We present the results from a search for gravitational-wave transients associated with core-collapse supernovae observed optically within 30 Mpc during the third observing run of Advanced LIGO and Advanced Virgo. No gravitational wave associated with a core-collapse supernova has been identified. We then report the detection efficiency for a variety of possible gravitational-wave emissions. For neutrino-driven explosions, the distance at which we reach 50% detection efficiency is up to 8.9 kpc, while more energetic magnetorotationally driven explosions are detectable at larger distances. The distance reaches for selected models of the black hole formation, and quantum chromodynamics phase transition are also …

Archaeology In Space: The Sampling Quadrangle Assemblages Research Experiment (Square) On The International Space Station. Report 1: Squares 03 And 05, Justin St. P. Walsh, Shawn Graham, Alice C. Gorman, Chantal Brousseau, Salma Abdullah

Art Faculty Articles and Research

Between January and March 2022, crew aboard the International Space Station (ISS) performed the first archaeological fieldwork in space, the Sampling Quadrangle Assemblages Research Experiment (SQuARE). The experiment aimed to: (1) develop a new understanding of how humans adapt to life in an environmental context for which we are not evolutionarily adapted, using evidence from the observation of material culture; (2) identify disjunctions between planned and actual usage of facilities on a space station; (3) develop and test techniques that enable archaeological research at a distance; and (4) demonstrate the relevance of social science methods and perspectives for improving life …

A Review Of Stable, Traversable Wormholes In F(R) Gravity Theories, Ramesh Radhakrishnan, Patrick Brown, Jacob Matulevich, Eric Davis, Delaram Mirfendereski, Gerald Cleaver

Physics and Astronomy Faculty Publications and Presentations

It has been proven that in standard Einstein gravity, exotic matter (i.e., matter violating the pointwise and averaged Weak and Null Energy Conditions) is required to stabilize traversable wormholes. Quantum field theory permits these violations due to the quantum coherent effects found in any quantum field. Even reasonable classical scalar fields violate the energy conditions. In the case of the Casimir effect and squeezed vacuum states, these violations have been experimentally proven. It is advantageous to investigate methods to minimize the use of exotic matter. One such area of interest is extended theories of Einstein gravity. It has been claimed …

The Nature Of X-Rays From Young Stellar Objects In The Orion Nebula Cluster—A Chandra Hetgs Legacy Project, Norbert S. Schulz, David P. Huenemoerder, David A. Principe, Marc Gagné, Hans Mortiz Günther, Joel Kastner, Joy Nichols, Andrew Pollock, Thomas Preibisch, Paola Testa, Fabio Reale, Fabio Favata, Claude R. Canizares

Earth & Space Sciences Faculty Publications

The Orion Nebula Cluster (ONC) is the closest site of very young (∼1 Myr) massive star formation The ONC hosts more than 1600 young and X-ray bright stars with masses ranging from ∼0.1–35 Me. The Chandra HETGS Orion Legacy Project observed the ONC with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 2.1 Ms. We describe the spectral extraction and cleaning processes necessary to separate overlapping spectra. We obtained 36 high-resolution spectra, which include a high-brilliance X-ray spectrum of θ1 Ori C with over 100 highly significant X-ray lines. The lines show Doppler broadening between 300 and 400 km …

General Relativistic Gravity In Core-Collapse Supernova Simulations, James Nicholas Roberts Ii

Doctoral Dissertations

Core-collapse supernovae (CCSNe) are some of the most extreme and complex phenomena in the universe. The toolkit for high-order neutrino-radiation hydrodynamics (thornado) is being developed to simulate CCSNe which will provide insight into the mechanisms underlying these events. The thornado framework is a collection of modules used to calculate the effects of gravity, hydrodynamics, neutrino transport, and nuclear physics through the Weaklib equation of state table. This dissertation will present the development of the Poseidon code, which provides the general relativistic gravity solver for the thornado framework.

The Poseidon code solves for the general relativistic metric using the xCFC formulation …

Comparison Of Core-Collapse Supernova Explosions With 15 Solar Mass Progenitors, Chien-Hui Chen

Masters Theses

The study of core-collapse supernovae (CCSNe) helps us understand the origin and history of chemical abundances in our Universe. Previous numerical studies of CCSNe have shown the importance of non-radial motion in pre-collapse progenitors on the explosion outcome. In this thesis, I use the 2D Chimera neutrino radiation hydrodynamics code to run simulations of four models with 15 solar mass (M⊙) progenitors but different initial conditions sourced from different 1D and 2D pre-collapse burning environments. To analyze the models, I compare the explosion evolution of their nuclear abundances, shocks, neutrino heating, accretion, explosion geometry, and turbulent convection. Despite the differences …

Analyzing Hubble Space Telescope Images Of Agn Host Galaxies With Keck Integral Field Spectra, Sebastian Contreras

Physics

In the center of most massive galaxies is a supermassive black hole (SMBH) with a mass that can range from millions to billions of solar masses. It has been observed that more massive SMBHs have a more massive host galaxy bulge, as evidenced by the larger bulge luminosity and stellar velocity dispersion, a correlation known as the BH mass - host-galaxy scaling relation. It suggests a close evolutionary connection between the growth of the SMBH and the growth of its host galaxy. If a SMBH develops an accretion disk to fuel an active galactic nucleus (AGN), it will emit radiation …

Rapid Parameter Estimation Of Gravitational Wave Sources & Homologous Expansion In Common Envelope Events, Vinaya Valsan

Theses and Dissertations

Binary star systems are crucial for advancing our understanding of the universe. My doctoral research focuses on two related topics within the domain of binary star dynamics: gravitational waves from compact binary stars, and the evolution of the common envelope in stellar mass binaries.

In the era of multi-messenger astrophysics, swift identification and characterization of gravitational wave events is important for subsequent electromagnetic observations. The development of low-latency parameter estimation techniques is essential for providing astronomers with crucial information regarding the potential electromagnetic counterparts to gravitational wave signals. RapidPE is a highly parallelized parameter estimation scheme that achieves low-latency parameter …

Observation Of Gravitational Waves From The Coalescence Of A 2.5–4.5 M⊙ Compact Object And A Neutron Star, A. Abac, R. Abbott, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We report the observation of a coalescing compact binary with component masses 2.5–4.5 M⊙ and 1.2–2.0 M⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO–Virgo–KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory. The primary component of the source has a mass less than 5 M⊙ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find …

An Analysis Of The Propagation Of Gravitational Radiation Under A Graviton Of Nonzero Mass And Its Implications For Cosmological Measurements, Margaret Johnston

UNLV Theses, Dissertations, Professional Papers, and Capstones

Under the assumptions of General Relativity (GR), gravitational waves propagate at the speed of light and their mediation can be represented as a particle through a massless graviton. We investigate the impact and observability of the presence of a massive graviton, how such a modification to GR would also modify the observed gravitational waves from astrophysical sources, and how this effect can be used as an independent measurement of cosmmological parameters, including the Hubble parameter H0. We simulate the impact of a massive graviton on compact binary coalescence observation in a near-future LIGO-Virgo-KAGRA interferometer network through a modification to the …

Answers To Frequently Asked Questions About The Pulsar Timing Array Hellings And Downs Curve, Joseph D. Romano, Bruce Allen

Physics and Astronomy Faculty Publications and Presentations

We answer frequently asked questions (FAQs) about the Hellings and Downs correlation curve—the ‘smoking-gun’ signature that pulsar timing arrays (PTAs) have detected gravitational waves (GWs). Many of these questions arise from inadvertently applying intuition about the effects of GWs on LIGO-like detectors to the case of pulsar timing, where not all of it applies. This is because Earth-based detectors, like LIGO and Virgo, have arms that are short (km scale) compared to the wavelengths of the GWs that they detect (≈102–104 km). In contrast, PTAs respond to GWs whose wavelengths (tens of light-years) are much shorter than their arms (a …

Space Radiation Assessment And Mitigation: Meeting The Growing Demand For Shielding Solutions By Enhancing Models And Exploring Novel Shielding Opportunities, M. Laura Sorgi Johann

Doctoral Dissertations and Master's Theses

The rapid growth of satellite technology and the increasing presence of vulnerable technology and human life in space have highlighted the need for improved shielding materials. Industry standard protocols for shielding are being pushed to their limits as we gain a deeper understanding of the harsh space environment and as chip sizes approach the scale of radiation wavelengths. Furthermore, the commercialization of space is attracting interest from industries such as pharmaceuticals and semiconductor crystal growing, as they explore the potential benefits of zero-gravity production environments. However, the eagerness to develop lighter shielding and the lack of consideration for existing tools …

Identifying The O’Connell Effect In Eclipsing Binary Stars, Nicholas Paolella

Computer Science and Information Technology Faculty

Data science techniques have wide-ranging applications throughout scientific explorations. One, is filtering astronomical data to better understand specific populations, such as binary stars. Specifically, binary stars that exhibit the O’Connell effect are worthy of study as this phenomenon is still not well understood. The O’Connell effect can be defined as the asymmetry of maxima in the light curves, as captured by the instrument, while observing the eclipsing binary system in question. There is significant data captured by NASA and curated by Villanova University, which enabled the investigation of eclipsing binary stars and the attributes of which may help identify the …

Variable Radio Emission Of Neutron Star X-Ray Binary Ser X–1 During Its Persistent Soft State, E. C. Pattie, Thomas J. Maccarone, Alexandra J. Tetarenko, James C. A. Miller-Jones, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval

Physics and Astronomy Faculty Publications and Presentations

Ser X–1 is a low-mass neutron star X-ray binary and has been persistently accreting since its discovery in the 1960s. It has always been observed to be in a soft spectral state and has never showed substantial long-term X-ray variability. Ser X–1 has one previous radio observation in the literature in which radio emission was detected during this soft state, which is contrary to the behavior of black hole X-ray binaries. We have recently obtained 10 randomly sampled radio epochs of Ser X–1 in order to further investigate its anomalous soft-state radio emission. Out of 10 epochs, we find 8 …

Evaluating Spatial Clustering As A Lunar Crater Classification Method, Annalyse Dickinson

Physics and Astronomy Summer Fellows

Crater identification is important for investigating and determining the age of planetary surfaces. Based on the number of primary craters—which are formed from a bolide impacting a planetary surface—one can determine the surface’s absolute model age, but the secondary craters—which are formed from the many fragments ejected during a primary crater’s creation—contaminate that count. The abundant variability in crater identification methods is a prominent issue in the field of planetary science. In addition, there is no single characteristic that can set these craters apart due to the processes involved in their formation and degradation. This is why we aim to …

Lunar Crater Categorization And Why Accessibility Matters For Planetary Scientists, Gavin Soueidan, Mckenzie Snyder

Physics and Astronomy Summer Fellows

One can determine the absolute model age of any planetary body in the solar system by compiling statistics about primary craters. However, secondary craters contaminate those statistics. Differentiating between primary craters—which are formed from an impact of an object from space onto a planetary surface—and secondary craters—which are formed from the fragments ejected from primaries—is an outstanding question in planetary science literature. No one characteristic can universally distinguish primaries from secondaries, and workers have developed numerous methods for sorting the two classes of craters. This is why we are developing a semi-automated, transparent, reproducible procedure that will compile datasets that …

Hierarchical Search Method For Gravitational Waves From Stellar-Mass Binary Black Holes In Noisy Space-Based Detector Data, Yao Fu, Yan Wang, Soumya D. Mohanty

Physics and Astronomy Faculty Publications and Presentations

Future space-based laser interferometric detectors, such as LISA, will be able to detect gravitational waves (GWs) generated during the inspiral phase of stellar-mass binary black holes (SmBBHs). These detections contain a wealth of important information concerning astrophysical formation channels and fundamental physics constraints. However, the detection and characterization of GWs from SmBBHs poses a formidable data analysis challenge, arising from the large number of wave cycles that make the search extremely sensitive to mismatches in signal and template parameters in a likelihood-based approach. This makes the search for the maximum of the likelihood function over the signal parameter space an …

Numerical Simulations Suggest Asteroids (101955) Bennu And (162173) Ryugu Are Likely Second Or Later Generation Rubble Piles., K J Walsh, R-L Ballouz, W F Bottke, C Avdellidou, Harold Connolly Jr., M Delbo, D N Dellagiustina, E R Jawin, T Mccoy, P Michel, T Morota, M C Nolan, S R Schwartz, S Sugita, D S Lauretta

School of Earth & Environment Departmental Research

Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but …

The Large-Scale Environments Of Active Galactic Nuclei, Grayson C. Petter

Dartmouth College Ph.D Dissertations

It is now recognized that the energy released by accreting supermassive black holes observed as Active Galactic Nuclei (AGN) is integral in shaping the dynamics of baryons on up to cosmological scales, and AGN thus play a significant role in regulating the formation and evolution of galaxies. Studying the clustering properties of AGN reveals which environments they release this feedback energy into, testing models of AGN-galaxy coevolution and AGN structure. In this thesis, I leverage wide-area photometric and spectroscopic survey data to measure the clustering properties of various AGN samples containing millions of systems, placing tight constraints on the properties …

Search For Gravitational-Lensing Signatures In The Full Third Observing Run Of The Ligo–Virgo Network, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

Gravitational lensing by massive objects along the line of sight to the source causes distortions to gravitational wave (GW) signals; such distortions may reveal information about fundamental physics, cosmology, and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO-Virgo network. We search for repeated signals from strong lensing by (1) performing targeted searches for subthreshold signals, (2) calculating the degree of overlap among the intrinsic parameters and sky location of pairs of signals, (3) comparing the similarities of the spectrograms among pairs of …

A Class Of Stable Nonlinear Non-Hermitian Skin Modes, Hamed Ghaemi-Dizicheh

Physics and Astronomy Faculty Publications and Presentations

The non-Hermitian skin effect (NHSE) is a well-known phenomenon in open topological systems that causes a large number of eigenstates to become localized at the boundary. Although many aspects of its theory have been investigated in linear systems, this phenomenon remains novel in nonlinear models. In the first step of this paper, we look at the conditions for the presence of quasi-skin modes in a semi-infinite, one-dimensional, nonlinear, nonreciprocal lattice. In the following phase, we explore the survival time of the quasi-skin mode in a finite nonlinear lattice with open edges. We study the dependency of the survival time on …

Optimal Reconstruction Of The Hellings And Downs Correlation, Bruce Allen, Joseph D. Romano

Physics and Astronomy Faculty Publications and Presentations

Pulsar timing arrays (PTAs) detect gravitational waves (GWs) via the correlations they create in the arrival times of pulses from different pulsars. The mean correlation, a function of the angle between the directions to two pulsars, was predicted in 1983 by Hellings and Downs (HD). Observation of this angular pattern is the ``smoking gun'' that GWs are present, so PTAs ``reconstruct the HD curve'' by estimating the correlation using pulsar pairs separated by similar angles. Several studies have examined the amount by which this curve is expected to differ from the HD mean. The variance arises because (a) a finite …

The Application Of Elastic Distance In Astrophysical Time Series, Xiyang Zhang

Electronic Thesis and Dissertation Repository

Elastic distances, e.g. dynamic time warping (DTW), evaluate the similarity between query and reference sequences by dynamic programming. The 1-Nearest-Neighbor predictor with DTW is one benchmark in time series classification. However, DTW is less efficient in astronomical time series because of ignorance of the information in time stamps and its dependence on the shape and magnitude between query and reference sequences. We apply two elastic distances which integrate the information in the time domain, time warp editing distance (TWED) and Skorohod distance, which is calculated by using Fre ́chet distance, to three astronomical datasets to compare with DTW and Euclidean …

On The Impact Of Geospace Weather On The Occurrence Of M7.8/M7.5 Earthquakes On 6 February 2023 (Turkey), Possibly Associated With The Geomagnetic Storm Of 7 November 2022, Dimitar Ouzounov, Galina Khachikyan

Mathematics, Physics, and Computer Science Faculty Articles and Research

A joint analysis of solar wind, geomagnetic field, and earthquake catalog data showed that before the catastrophic M = 7.8 and M = 7.5 Kahramanmaras earthquake sequence on 6 February 2023, a closed strong magnetic storm occurred on 7 November 2022, SYM/H = −117 nT. The storm started at 08:04 UT. At this time, the high-latitudinal part of Turkey’s longitudinal region of future epicenters was located under the polar cusp, where the solar wind plasma would directly access the Earth’s environment. The time delay between storm onset and earthquake occurrence was ~91 days. We analyzed all seven strong (M7+) earthquakes …