Astrophysics and Astronomy Commons^™

Remnant Polarization And Structural Arrangement In P(Vdf-Trfe) Electrospun Fiber Meshes Affect Osteogenic Differentiation Of Human Mesenchymal Stromal Cells, Bahareh Azimi, Massimiliano Labardi, Mohammad Sajad Sorayani Bafqi, Teresa Macchi, Claudio Ricci, Veronica Carnicelli, Lorenzo Scarpelli, Istiak Hussain, Francesca Matino, Mohammed Uddin

Physics & Astronomy Faculty Publications

Highlights

• The type of solvent had noticeable effects on morphology and piezoelectric properties of P(VDF-TrFE) electrospun fibers.

• Using MEK as a solvent and specific environmental conditions led to the obtainment of surface nanopores.

• Uniaxially aligned fibers exhibited higher β phase and mechanical properties than random ones.

• Randomly oriented fibers had higher remnant piezoelectric properties (Vout, d31 piezoelectric coefficient) than aligned ones.

• Human mesenchymal stem cells cultured on randomly oriented fibers showed an accelerated osteogenic differentiation.

Abstract

Many tissues and cells are influenced by mechano-electric stimulation, thus the application of piezoelectric materials has recently received considerable attention in tissue engineering. …

Search For Gravitational-Wave Transients Associated With Magnetar Bursts In Advanced Ligo And Advanced Virgo Data From The Third Observing Run, R. Abbott, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Gravitational waves are expected to be produced from neutron star oscillations associated with magnetar giant flares and short bursts. We present the results of a search for short-duration (milliseconds to seconds) and long-duration (∼100 s) transient gravitational waves from 13 magnetar short bursts observed during Advanced LIGO, Advanced Virgo, and KAGRA's third observation run. These 13 bursts come from two magnetars, SGR 1935+2154 and Swift J1818.0−1607. We also include three other electromagnetic burst events detected by Fermi-GBM which were identified as likely coming from one or more magnetars, but they have no association with a known magnetar. No magnetar giant …

Better Light Than Never: A New Radiative Mechanism For Observing Binary Black Holes, Paul Rioles

Graduate Masters Theses

Black holes are notoriously elusive, they are impossible to observe directly, and cur- rent methods of extracting information from behind their cosmic camouflage are both limited in number and experimentally difficult. The scope of this investigation is to ex- plore a proposed novel radiative mechanism for active similar mass binary black holes, affording new observational methods to investigate frequency inspirals of BH mergers. The explored mechanism is a result of each BH’s accretion of the surrounding plasma, creating voids that orbit throughout the plasma. The significant results described in this thesis include expressions for the frequency, power radiated per unit …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

How Do Nuclear Isomers Influence The Gamma-Ray Bursts In Binary Neutron Star Mergers?, Maria Babiuc-Hamilton, Joseph I. Powell

Physics Faculty Research

Neutron star mergers are astrophysical “gold mines,” synthesizing over half of the elements heavier than iron through rapid neutron capture nucleosynthesis. The observation of the binary neutron star merger GW170817, detected both in gravitational waves and electromagnetic radiation, marked a breakthrough. One electromagnetic component of this event, the gamma ray burst GRB 170817A, has an unresolved aspect: the characteristics of its prompt gamma-ray emission spectrum. In this work, we investigate that gamma-ray spectra in such GRBs may be influenced by de-excitations from isomeric transitions. Our study begins with a review of current knowledge on GRB structure and of r-process nucleosynthesis …

Local Map Of The Interstellar Fuv Field, David Lomeli

Open Access Theses & Dissertations

The strength of the far-ultraviolet field is an important parameter in determining the chemistry that takes place in star-forming regions. FUV radiation is produced by bright stars in the galaxy and absorbed by interstellar dust. By using newly available maps of the dust distribution, in conjunction with catalogs of stellar positions and spectra, we created a local map of the FUV field ranging from 6-13.6 eV. We find a value of 6.57*10^-14 erg/cm^3 at the location of the Sun. This value, alongside its spectra, follow previous measurements and estimates of the FUV field at the Sun. We further study the …

Modeling The Spatiotemporal Variations Of The Magnetic Field In Active Regions On The Sun Using Deep Neural Networks, Godwill Asare Mensah Mensah

Open Access Theses & Dissertations

Solar active regions are areas on the Sun's surface that have especially strong magnetic fields. Active regions are usually linked to a number of phenomena that can have serious detrimental consequences on technology and, in turn, human life. Examples of these phenomena include solar flares and coronal mass ejections, or CMEs. The precise predictionof solar flares and coronal mass ejections is still an open problem since the fundamental processes underpinning the formation and development of active regions are still not well understood. One key area of research at the intersection of solar physics and artificial intelligence is deriving insights from …

Spin Disorder Control Of Topological Spin Texture, Hongrui Zhang, Yu-Tsun Shao, Xiang Chen, Binhua Zhang, Tianye Wang, Fanhao Meng, Kun Xu, Peter Meisenheimer, Xianzhe Chen, Xiaoxi Huang, Piush Behera, Sajid Husain, Tiancong Zhu, Hao Pan, Yanli Jia, Nick Settineri, Nathan Giles-Donovan, Zehao He, Andreas Scholl, Alpha N'Diaye, Padraic Shafer, Archana Raja, Changsong Xu, Lane W. Martin, Michael F. Crommie, Jie Yao, Ziqiang Qiu, Arun Majumdar, Laurent Bellaiche, David A. Muller, Robert J. Birgeneau, Ramamoorthy Ramesh

Physics Faculty Publications and Presentations

Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe₃GaTe₂, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights …

Algorithm-Based Linearly Graded Compositions Of Gesn On Gaas (001) Via Molecular Beam Epitaxy, Calbi Gunder, Mohammad Zamani-Alavijeh, Emmanuel Wangila, Fernando Maia De Oliveira, Aida Sheibani, Serhii Kryvyi, Paul C. Attwood, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo

Physics Faculty Publications and Presentations

The growth of high-composition GeSn films in the future will likely be guided by algorithms. In this study, we show how a logarithmic-based algorithm can be used to obtain high-quality GeSn compositions up to 16% on GaAs (001) substrates via molecular beam epitaxy. Herein, we use composition targeting and logarithmic Sn cell temperature control to achieve linearly graded pseudomorph Ge_1−xSn_x compositions up to 10% before partial relaxation of the structure and a continued gradient up to 16% GeSn. In this report, we use X-ray diffraction, simulation, secondary ion mass spectrometry, and atomic force microscopy to analyze and …

To The Torus And Beyond: An X-Ray Study Of Agn Tori Morphology, Andrealuna Pizzetti

All Dissertations

Active Galactic Nuclei (AGN) are among the Universe's most energetic and powerful objects, fueled by an accreting supermassive black hole (SMBH) at the host galaxy's center, surrounded by a toroidal structure of dusty gas. Ultraviolet photons arising from the accretion disk get up-scattered to X-rays via inverse Compton scattering by hot electrons close to the accretion disk. Being produced in the very center of the AGN, X-ray photons are powerful messengers that probe the physics of the accretion system and the matter in the surroundings. The torus, formerly considered homogeneous, appears to be a more complex structure of clouds with …

The Gravitational Wave Peep: Improved Modeling Of Highly Eccentric Emris For Lisa Signal Confusion Noise, Daniel Joseph Oliver

Graduate Theses and Dissertations

Scattering events around a massive black hole will occasionally toss a stellar-mass compact object into an orbit around the massive black hole, beginning an extreme mass ratio inspiral. The early stages of such a highly eccentric orbit will not produce detectable gravitational waves as the source will only be in a suitable frequency band briefly when it is close to periapsis during each long-period orbit. This burst of emission, firmly in the millihertz band, is the gravitational wave peep. While a single peep is not likely to be detectable, if we consider an ensemble of such subthreshold sources, spread across …

Dynamical Studies Of Misaligned Circumbinary Disks, Ian C. Rabago

UNLV Theses, Dissertations, Professional Papers, and Capstones

Binary stars are common outcomes of the star formation process, with nearly half of Sun-like stars forming as part of a binary pair. The presence of a second star adds additional complexity and dynamical effects to the planet formation process in the surrounding circumbinary disk. In this work, I investigate the behavior of a circumbinary disk using hydrodynamic modeling, specifically in the case where the disk is misaligned to the binary orbital plane. Around eccentric binaries, highly inclined disks can align themselves perpendicular to the binary orbital plane. These "polar disks'' can produce vortices and spiral arms when the disk …

Understanding Disk Substructures With 3d Self-Consistent Thermodynamics, Shangjia Zhang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Protoplanetary disks are birthplaces of planets. The past decade witnessed a great advance- ment in disk observations by Atacama Large Millimeter Array (ALMA) and extreme adaptive optics (ExAOs). Hundreds of disks have been observed at high angular resolutions and revealed rich substructures (e.g., gaps/rings) at midplane and atmosphere, at least part of which are per- turbed by planets. Deep understanding of disk physics has a great potential to unveil more young planets from substructures and distinguish those that are not caused by planets. I worked on con- straining young planet populations using planet-disk interaction simulations and substructures and self-consistent treatment …

Unraveling The Physics Of Quasar Jets Using Hst Polarimetry, Devon Clautice

Theses and Dissertations

We present a multiwavelength study of three high-power FR II (quasar) jets -- 3C 273, PKS 0637-752, and 1150+497 -- with an emphasis on new high-quality Hubble Space Telescope (HST) optical polarimetry and Chandra X-ray Observatory imaging. Relativistic jets from active galactic nuclei transport energy and mass from the supermassive black hole’s accretion region out to Megaparsec-scale lobes, with effects that feedback into galaxy formation and cluster energetics. We build on recent work which has called into question our fundamental understanding of FR II jet physics, and suggest that highly-efficient particle acceleration must be taking place in situ …

Mapping Star Formation Histories In Nearby Galaxies To Source Lyman Continuum Photon Escape, Katie Kudla '24

Engineering & Physics Student Scholarship

Katie Kudla ’24, Physics major
Faculty Mentor: Dr. Joseph Ribaudo, Engineering and Physics

Investigation Of Surface Chemistry From Electron Irradiation Of Synthetic Schreibersite, Tyler Davis

Master's Theses

While phosphorus is one of the key elements for life on Earth, it has relatively low abundance in extraterrestrial environments, making it a target for astronomers and astrobiologists interested in the possibility of life beyond our planet. Schreibersite (Fe,Ni)₃P is one of the first P-containing minerals to condense during planetary cooling and one of the primary P-containing minerals in iron and stony-iron meteorites. Therefore, it is a likely P-bearing mineral in cometary cores and dust grains within the interstellar medium and circumstellar envelopes. Experiments in this project were performed with the aim of observing the formation of small …

Models Of Low Mass Stars As Physical Labratories, Emily M. Boudreaux

Dartmouth College Ph.D Dissertations

Low mass stars account for approximately 70 percent of the stellar populations (Conroy & Van Dokkum, 2012); yet, due to their small sizes and cool temperatures they account for only a small fraction of the galaxies luminosity function (Laughlin et al., 1997). Moreover, due to the lack of laboratory conditions available to astronomy and astrophysics low mass stars can provide a rare controlled environment for calibrations of numerical models. Consequently, across multiple domains there has been significant interest in these key astronomical objects. In this thesis I present three projects which have further revealed properties of low mass stars and …

Significance And Reflection Of Lunar Exploration, Jiaqi Liu

Bulletin of Chinese Academy of Sciences (Chinese Version)

Although China's lunar exploration project started later than the Soviet Union and the United States, it is the first country to land probes and retrieve samples on both the right side and the reverse side of the Moon. There have been many major breakthroughs in space technology, and many important achievements in scientific research as well. It has extended the life of the Moon for about 1 billion years.

Modeling An Extra Planet's Effects On Earth, Emily Simpson

Aerospace, Physics, and Space Science Student Publications

Orbital dynamics play a crucial role in determining the habitability of exoplanets, and many models have been developed to study the dynamical evolution of broader planetary system structure. To further investigate the implications this has regarding planetary habitability, this project simulated the evolution of the Solar System with an additional planet orbiting in place of the Asteroid Belt using the Gravitational Rigid-body InTegrator (GRIT) package. 21 total simulations were run for 100,000 years with varying values for the extra planet’s mass (from 0.01 to 10 Earth masses) and orbital parameters (based on the 4 most massive asteroids in the Asteroid …

A Distinct Radial Acceleration Relation Across The Brightest Cluster Galaxies And Galaxy Clusters, Pengfei Li, Stacy S. Mcgaugh

Faculty Scholarship

Recent studies reveal a radial acceleration relation (RAR) in galaxies, which illustrates a tight empirical correlation connecting the observational acceleration and the baryonic acceleration with a characteristic acceleration scale. However, a distinct RAR has been revealed on brightest cluster galaxy (BCG) cluster scales with a seventeen-times-larger acceleration scale due to the gravitational lensing effect. In this work, we systematically explore the acceleration and mass correlations between dynamical and baryonic components in 50 BCGs. To investigate the dynamical RAR in BCGs, we derived their dynamical accelerations from the stellar kinematics using the Jeans equation through Abel inversion and adopted the baryonic …

A New Effective Gravitational Lensing Approach To Constrain Dark Matter, Birendra Dhanasingham

Physics & Astronomy ETDs

Galaxy-scale strong gravitational lenses offer a unique window into understanding the nature and distribution of dark matter at sub-galactic scales. Beyond the main-lens subhalos, the inclusion of line-of-sight dark matter halos has become essential in lens studies due to their substantial role in perturbing lensed images, making multi-plane lensing a crucial aspect of any lens study. We highlight that these line-of-sight halos appear extended tangentially along the lensing critical line in the effective convergence maps due to the nonlinear nature of multiplane lensing, resulting in a characteristic anisotropic signature in the deflection field. Leveraging tools from large-scale structure analyses, this …

Mapping Out The Sky, Erik Johnson

Natural Science Faculty

Astronomers are often asked to help identify UFOs. It's a reasonable request since the term means "unidentified flying object." An untrained observer may not know which celestial objects are visible at night, even in light-polluted skies. They may mistake a plane for a planet, a bright star, or a satellite.

Quantum Computation Using Large Spin Qudits, Sivaprasad Thattupurackal Omanakuttan

Physics & Astronomy ETDs

This dissertation explores quantum computation using qudits encoded into large spins, emphasizing the concept of quantum co-design to harness the unique capabilities of physical platforms for enhanced quantum information processing. First, we delve into the generation of high-fidelity universal gate sets for quantum computation with qudits. Leveraging principles from quantum optimal control, Rydberg physics, and the atomic structure of alkaline-earth atoms, we propose protocols for high-fidelity universal gate sets in the ground state of ⁸⁷Sr with reasonable experimental parameters. Next, we analyze schemes to encode a qubit in the large spin qudits for fault-tolerant quantum computation (FTQC). By comprehending …

Simulating Continuous Gravitational Waves, Ivan Mihael Villalba Moran

SACAD: Scholarly Activities

Using a table-top Michelson Interferometer to replicate Laser Interferometer Gravitational-Wave Observatory (LIGO) arrangement, we use sound waves to simulate Continuous Gravitational Waves (CWs). Using the NumPy package in Python programming, we recover the frequency of the injected sinusoidal signal using the mathematics of the Fourier Transform. Currently, we are trying to implement the Hidden Markov Model along with the Viterbi Algorithm as a method to detect Wandering Continuous Gravitational Waves.

The Jesuit Tradition Of Astronomy At Holy Cross, Sarah Campbell M.A., M.S.I.S.

Staff publications

This paper summarizes the study of astronomy and related fields as part of the curriculum at the College of the Holy Cross. It briefly profiles four Jesuit priests who were associated with Holy Cross and made significant contributions to the study of astronomy, solar physics and other scientific disciplines. The history of a campus observatory is briefly described as well.

This paper was presented an event sponsored by the Holy Cross Libraries to commemmorate the solar exclipse which occurred April 8. 2024.

A Search For Intermediate-Mass Black Holes In Compact Stellar Systems Through Optical Emissions From Tidal Disruption Events, Richard T. Pomeroy, Mark A. Norris

Physics & Astronomy Faculty Publications

Intermediate-mass black holes (IMBH) are expected to exist in globular clusters (GCs) and compact stellar systems (CSS) in general, but none have been conclusively detected. Tidal disruption events (TDEs), where a star is tidally disrupted by the gravitational field of a black hole, have been observed to occur around the supermassive black holes (SMBH) found at the centres of galaxies, and should also arise around IMBHs, especially in the dense stellar cores of CSS's. However, to date none have been observed in such environments. Using data from the Zwicky Transient Facility (ZTF) we search for TDEs associated with CSS, but …

Search For Extreme Mass Ratio Inspirals Using Particle Swarm Optimization And Reduced Dimensionality Likelihoods, Xiao-Bo Zou, Soumya Mohanty, Hong-Gang Luo, Yu-Xiao Liu

Physics & Astronomy Faculty Publications

Extreme-mass-ratio inspirals (EMRIs) are significant observational targets for spaceborne gravitational wave detectors, namely, LISA, Taiji, and Tianqin, which involve the inspiral of stellar-mass compact objects into massive black holes (MBHs) with a mass range of approximately 104 ∼107��⊙ . EMRIs are estimated to produce long-lived gravitational wave signals with more than 105 cycles before plunge, making them an ideal laboratory for exploring the strong-gravity properties of the spacetimes around the MBHs, stellar dynamics in galactic nuclei, and properties of the MBHs itself. However, the complexity of the waveform model, which involves the superposition of multiple harmonics, as well as the …

Radial Acceleration Relation Of Galaxies With Joint Kinematic And Weak-Lensing Data, Tobias Mistele, Stacy S. Mcgaugh

Faculty Scholarship

We combine kinematic and gravitational lensing data to construct the Radial Acceleration Relation (RAR) of galaxies over a large dynamic range. We improve on previous weak-lensing studies in two ways. First, we compute stellar masses using the same stellar population model as for the kinematic data. Second, we introduce a new method for converting excess surface density profiles to radial accelerations. This method is based on a new deprojection formula which is exact, computationally efficient, and gives smaller systematic uncertainties than previous methods. We find that the RAR inferred from weak-lensing data smoothly continues that inferred from kinematic data by …

Phys 211h

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 918

Department of Physics and Astronomy: Syllabi

No abstract provided.