Astrophysics and Astronomy Commons^™

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.

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 …

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 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.

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 …

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.

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.

Phys 926

Department of Physics and Astronomy: Syllabi

No abstract provided.

Group Iv Topological Quantum Alloy And The Role Of Short-Range Order: The Case Of Ge-Rich Ge1–XPbX, Yunfan Liang, Shunda Chen, Xiaochen Jin, Damien West, Shui-Qing Yu, Tianshu Li, Shengbai Zhang

Electrical Engineering and Computer Science Faculty Publications and Presentations

Despite the explosion of interest in topological materials over the last decades, their applications remain limited due to challenges in growth and incorporation with today’s microelectronics. As a potential bridge to close this gap, we investigate the group-IV alloy Ge_1–xPb_x, in the Ge-rich condition using density functional theory and show that relatively low concentrations of Pb (~9.4%) can lead to a topological phase transition. Furthermore, the calculation of the Z₂ invariant for both the random alloy and the alloy with short-range order (SRO) indicate that the topological phase of the material can be directly modified …

Phys 401/801

Department of Physics and Astronomy: Syllabi

No abstract provided.

Creation Of Bound Half-Fermion Pairs By Solitons, Sapan Karki, Brett Altschul

Faculty Publications

In the presence of topologically nontrivial bosonic field configurations, the fermion number operator may take on fractional eigenvalues, because of the existence of zero-energy fermion modes. The simplest examples of this occur in 1+1 dimensions, with zero modes attached to kink-type solitons. In the presence of a kink-antikink pair, the two associated zero modes bifurcate into positive and negative energy levels with energies ±ge^-gΔ, in terms of the Yukawa coupling g≪1 and the distance Δ between the kink and antikink centers. When the kink and antikink are moving, it seems that there could be Landau–Zener-like transitions between these …

Phys 142

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 812

Department of Physics and Astronomy: Syllabi

No abstract provided.

Reevaluating The Origin Of Detectable Cataclysmic Variables In Globular Clusters: Testing The Importance Of Dynamics, Liliana Rivera Sandoval, Diogo Belloni, Miriam Ramos Arevalo

Physics & Astronomy Faculty Publications

Based on the current detectable cataclysmic variable (CV) population in Galactic globular clusters (GCs), we show that there is not a clear relation between the number of sources per unit of mass and the stellar encounter rate, the cluster mass, or the cluster central density. If any, only in the case of core-collapsed GCs could there be an anticorrelation with the stellar encounter rate. Our findings contrast with previous studies where clear positive correlations were identified. Our results suggest that correlations between faint X-ray sources, from which often conclusions for the CV population are drawn, and the GC parameters considered …

Factors Predicting Public’S Willingness To Support National Aeronautics And Space Administration’S Artemis Mission, Sean Crouse

Doctoral Dissertations and Master's Theses

NASA's Artemis program aspires to return astronauts to the moon and aims to land the first woman and person of color on the lunar surface. The endeavor symbolizes the next evolution in space exploration and serves as a testament to the human spirit of discovery. In the face of this significant undertaking, gauging public sentiment and understanding the factors driving public support becomes necessary. The current study aimed to address a critical gap in the literature by examining public support for NASA’s Artemis mission, which is essential for sustaining the program’s momentum and cultivating a culture of innovation and exploration. …

Self-Consistent Atmosphere Representation And Interaction In Photon Monte Carlo Simulations, J. R. Peterson, G. Sembroski, A. Dutta, C. Remocaldo

Purdue University Libraries Open Access Publishing Fund

We present a self-consistent representation of the atmosphere and implement the interactions of light with the atmosphere using a photon Monte Carlo approach. We compile global climate distributions based on historical data, self-consistent vertical profiles of thermodynamic quantities, spatial models of cloud variation and cover, and global distributions of four kinds of aerosols. We then implement refraction, Rayleigh scattering, molecular interactions, and Tyndall–Mie scattering to all photons emitted from astronomical sources and various background components using physics first principles. This results in emergent image properties that include: differential astrometry and elliptical point spread functions (PSFs) predicted completely to the horizon, …

Determining The Lightcurves And Rotational Periods Of Four Main Belt Asteroids, Kaitlyn Kalisek

Honors Theses

This research found lightcurves and rotational periods of four main belt asteroids, 2854 Rawson, 5142 Okutama, (14362) 1988 MH, and 28248 Barthelemy. The A&M-Commerce observatory 0.7 meter telescope equipped with a CCD camera was used to collect multiple nights of data for each asteroid which was then analyzed to determine the asteroid’s lightcurve, rotational period, and create a possible 3D model. The rotational periods were found to be 4.775 ± 0.001 h for 2854 Rawson, 3.803 ± 0.001 h for 5142 Okutama, 3.645 ± 0.001 h for (14362) 1988 MH, and 3.128 ± 0.002 h for 28248 Barthelemy.

Study Of Deep Learning Models To Classify Nasa’S Kepler Light Curves, Heena Minnich

Computer Science Theses & Dissertations

The search for exoplanets has been an ongoing effort since the first discoveries of planets beyond our solar system in the 1990s. Finding a potentially habitable planet outside our solar system could provide key insights on life elsewhere in the universe. NASA Missions such as the Kepler, launched in 2009 and completed in 2018, have provided a massive amount of data in this goal by using the transit method to discover repetitive and periodic dips in visible light around a star. The transit method has been used to measure flux, the brightness of a star over time. These flux time …

Characterizing And Mitigating Transient Noise In Ligo Observatories For Gravitational Wave Detection, Jane Glanzer

LSU Doctoral Dissertations

The existence of gravitational waves is predicted by Albert Einstein's Theory of General Relativity. Commonly referred to as "ripples in spacetime", these waves are generated by some of the most violent and energetic processes in the universe. Despite their theoretical prediction over a century ago, it wasn't until 2015 that the Advanced LIGO (aLIGO) interferometers in Hanford, WA and Livingston, LA directly detected gravitational waves for the first time, confirming Einstein's theory and ushering in a new era of astrophysics.

Detecting gravitational waves requires incredible precision. Because of the extreme sensitivity required, it is possible for the gravitational wave data …

A Joint Fermi-Gbm And Swift-Bat Analysis Of Gravitational-Wave Candidates From The Third Gravitational-Wave Observing Run, C. Fletcher, J. Wood, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search …

Poleward Moving Auroral Forms And Magnetic Reconnection, Gasia Excel, Gerard Fasel, Julia Johnson, Jordana Xu, Parker Para, Amiel Silbol, Rachel Rodriguez, John Mann

Seaver College Research And Scholarly Achievement Symposium

Magnetic reconnection on the dayside magnetosphere is one of the main mechanisms for the solar wind to transfer energy and momentum to the terrestrial environment. This process is assumed to be most effective 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. The PMAFs occurring for the positive/(negative) IMF y-component first expanded westward(dawn)/eastward(dusk) before propagating poleward. This PMAF study presents a comprehensive set of events where the initial brightening moves through a pre-existing dayside auroral arc westward(dawn)/eastward(dusk) when the IMF y-component …

Dayside Pulsating Diffuse Aurora And The Interplanetary Magnetic Field, Thomas Lewer, Gerard J. Fasel, Maxwell Fargo, Ethan Swonger, S. Lee, Aidan Hulbert, Owen Bradley, Arman Manookian, Tommy Cleaveland, B. Yonano, John Mann, F. Sigernes, D. Lorentzen

Seaver College Research And Scholarly Achievement Symposium

Changes in the interplanetary magnetic field (IMF) orientation can affect pulsations in the dayside aurora. It has been reported that multiple dayside arcs(Pc 5 band) were replaced by diffuse pulsating aurora (Pc 3-4 band) when the IMF turned northward. Dayside green (557.7 nm emission) pulsating aurora had been reported to occur between 0800 and 1100 MLT (0500-0800 UT) in patches. The pulsations are normally associated with Pc 3-5 range. This statistical study examines pulsating green aurora using ground-based optical data are obtained from the Kjell Henriksen Observatory (KHO) in Longyearbyen, Svalbard (GEO: N, E; AACGM: N, E). All-Sky Camera images …

The Infrared Absorption Spectrum Of Phenylacetylene And Its Deuterated Isotopologue In The Mid- To Far-Ir, Vincent J. Esposito, Pierro Ferrari, Wybren Jan Buma, Ryan C. Fortenberry, Christiaan Boersma, Alessandra Candian, Alexander G. G. M. Tielens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Anharmonicity strongly influences the absorption and emission spectra of polycyclic aromatic hydrocarbon (PAH) molecules. Here, IR–UV ion-dip spectroscopy experiments together with detailed anharmonic computations reveal the presence of fundamental, overtone, as well as 2- and 3-quanta combination band transitions in the far- and mid-infrared absorption spectra of phenylacetylene and its singly deuterated isotopologue. Strong absorption features in the 400–900 cm⁻¹ range originate from CH(D) in-plane and out-of-plane wags and bends, as well as bending motions including the C≡C and CH bonds of the acetylene substituent and the aromatic ring. For phenylacetylene, every absorption feature is assigned either directly or …

Neutrino’S Non-Zero Electric Potential As An Origin Of Gravitation, Domain Structure And Expansion Of The Universe., Polievkt Perov

College of Arts & Sciences Faculty Works

The axial electric potentials of neutrinos as neutral composite structures, while being very small at large distances, do not vanish, and the same can be said about the neutrino “asymmetric dipoles” (paired neutrinos of not the same kind). Depending on the orientation of the “asymmetric dipole”, its far-field electric potential in some direction can be positive or negative, interacting with other “dipoles” at that large distance attractively or repulsively depending on their mutual orientation. The mutual orientation of the dipoles locally (inside a galaxy) might be such that they are aligned and experience the attractive force toward the local center …