Astrophysics and Astronomy Commons^™

A Sequential Quadratic Programming Approach To Coupling‐Bounded Non‐Inertial Earthquake Cycle Kinematics With Distance‐Weighted Eigenmodes, Brendan J. Meade, John P. Loveless

Astronomy: Faculty Publications

Geologic and geodetic observations provide constraints on tectonic and earthquake cycle kinematics. Block models offer one approach to integrating the effects of plate rotations, elastic strain accumulation, applied basal displacements, internal block strain, and idealized pressure sources. Here, we describe the construction of block models where spatially variable slip rates are parameterized by distance‐weighted eigenmodes operating over meshes of triangular dislocation elements. This dimensionally reduced model is recast as a quadratic programming problem with upper and lower bounds on both geologic fault slip rates and spatially variable slip deficit rates. We propose iterating over successive quadratic programming estimates with evolving …

Light Nuclei Femtoscopy And Baryon Interactions In 3 Gev Au+Au Collisions At Rhic, The Star Collaboration

Physics and Astronomy Faculty Publications

We report the measurements of proton-deuteron (𝑝-𝑑) and deuteron-deuteron (𝑑-𝑑) correlation functions in Au+Au collisions at √𝑠NN = 3 GeV using fixed-target mode with the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). For the first time, the source size (𝑅 𝐺), scattering length (𝑓0), and effective range (𝑑0) are extracted from the measured correlation functions with a simultaneous fit. The spin-averaged 𝑓0 for 𝑝-𝑑 and 𝑑-𝑑 interactions are determined to be -5.28 ± 0.11(stat.) ± 0.82(syst.) fm and -2.62 ± 0.02(stat.) ± 0.24(syst.) fm, respectively. The measured 𝑝-𝑑 interaction is consistent with theoretical calculations and low- energy scattering experiment …

Electric-Charge-Dependent Directed Flow Splitting Of Produced Quarks In Au+Au Collisions, The Star Collaboration

Physics and Astronomy Faculty Publications

We report directed flow (𝑣1) of multistrange baryons (Ξ and Ω) and improved 𝑣1 data for 𝐾−, ̄ 𝑝, ̄ Λ and 𝜙 in Au+Au collisions at √𝑠NN =27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (“splitting”) for combinations having non-identical quark content. Under the assumption of quark …

Measurement Of Directed Flow In Au+Au Collisions At √Snn = 19.6 And 27 Gev With The Star Event Plane Detector, Star Collaboration

Physics and Astronomy Faculty Publications

In heavy-ion collision experiments, the global collectivity of final-state particles can be quantified by anisotropic flow coefficients (vn). The first-order flow coefficient, also referred to as the directed flow (v1 ), describes the collective sideward motion of produced particles and nuclear fragments in heavy-ion collisions. It carries information on the very early stage of the collision, especially at large pseudorapidity (η), where it is believed to be generated during the nuclear passage time. Directed flow therefore probes the onset of bulk collective dynamics during thermalization, providing valuable experimental guidance to models of the pre-equilibrium stage. In 2018, the Event Plane …

Suntan (And Other Solar Trigonometric Functions): Solutions For Fermi Questions: February 2025, John Adam

Mathematics & Statistics Faculty Publications

The article discusses the intensity of sunlight on the side of the author's face as they walk to and from their office, focusing on the solar zenith angle θ. It presents a formula for solar irradiance and explores how the intensity changes based on the angle and elevation. The solutions to the questions posed in the article provide insights into the maximum irradiance levels at different angles and elevations.

Nonlinear Wave Dynamics In Asteroseismology With Application To Delta Scuti Stars, Mohammed Mourabit

Physics Dissertations - Archive

This thesis compiles the collection of works in nonlinear astroseismology and its implication to the δ Sct variable that we carried over the course of five years. With the advent of high-resolution space missions such as the Kepler and TESS telescopes, we were able to see significant progress in the field in recent years. Nonetheless the new technologies also brought an increasing number of observation that are seemingly contradictory to the linear theory of asteroseismology. In particular, we find the δ Sct variable, which eludes our models in terms of how varied we find they spectra for stars with very …

Hardware Implementation Of An Efficient Frequency Comb Generator For Microwave Kinetic Inductance Detectors, Frank Atobrah Danso

Open Access Master's Theses

The frequency comb generator is an essential component in the readout of superconducting detectors. This component is responsible for generating the resonant frequencies necessary to detect photon interaction with the detectors. This component however has not received the much needed attention in terms of readout systems optimization. Conventional implementations rely on either inverse fast Fourier transform (IFFT) engines, which scale poorly in power with increasing frequency resolution requirement but allow flexible tone updates, or lookup tables (LUTs), which demand large memory for high frequency resolution.

Microwave Kinetic Inductance Detectors (MKIDs) are superconducting detectors which have gained significant interest for cryogenic …

A Multispectral Analysis Of High Redshift Quasars And Their Energy Production Mechanisms, Erik Carlson

Open Access Dissertations

We present a complete sample of radio-loud (P_3.0 GHz = 10^27.26 W/Hz) high-redshift (z ≥ 2.5) quasars in the Northern Hemisphere (δ ≥ 0). Each source was imaged with a user-defined imaging protocol developed for the Very Large Array Sky Survey. Higher-resolution images were generated from archival observations and new Enhanced Very Large Array observations (Project Code: 24B-010).  We produced 407 images of galaxies, where we are likely the first humans to see them. Twenty of these sources were high-redshift jets which increased the number of known high-redshift jets by 69%. This sample represents one of the largest …

Pave Outer Space And Put Up A Parking Lot: Lagrange Points Should Be The Common Heritage Of Mankind, David A. Koplow

Michigan Journal of International Law

Outer space offers a vast array of opportunities, with different locations or regions available for exploitation by diverse users for a growing variety of satellite functions. But not all sectors of space are equally valuable for all applications, and the most desirable venues can become crowded, affording a premium for those who gain access first and impeding the development of a fair and efficient all-inclusive international legal regime.

This article focuses on Lagrange points, a finite series of special locations in space where the gravitational forces from a pair of large celestial bodies interact in unusual ways. These points afford …

Scaling Laws For Diffusion In Crystallized Plasma From Molecular Dynamics, Dany Yaacoub

Theses and Dissertations

Diffusion coefficients for crystallized Coulomb plasmas are essential microphysics input for modeling white dwarf cores and neutron star crusts. Solving for diffusion coefficients require running large molecular dynamics simulations with thousands of particles over millions of timesteps. The diffusion in a crystallized plasma has been largely ignored and is often taken to be zero in stellar evolution codes. We find that not only is this incorrect, but we find that the diffusion in a crystallized plasma can be modeled completely using a universal scaling law independent of screening. Our simulations also show that the dominant mode of diffusion in a …

Stars, Statutes, And Sharing: Designing Global Ip Frameworks For Space-Based Discoveries, Ed Koellner

Marquette Intellectual Property & Innovation Law Review

As humanity stretches farther into space physically, commercially, and intellectually, contemporary legal frameworks are beginning to creak under the pressure. Intellectual property laws seem to be playing catch-up. Those laws were written for a world bound by borders and gravity, not for orbital labs, the Earth’s Moon, or AI-generated inventions drifting above the Earth.

This article takes a closer look at the increasingly complex intersection of space law, intellectual property, and artificial intelligence. This domain is no longer reserved for state-led missions or high-level treaties. Now and in the near future, a university lab or a private startup might be …

Boy Whose Head Was Filled With Stars: A Life Of Edwin Hubble (2021) By Isabelle Marinov, Maughn Rollins Gregory

Picture Books

Barely a hundred years ago, Edwin Hubble changed the way we understand the universe and our place in it more dramatically than almost anyone else has ever done. As this picture book biography shows, his mind-boggling discoveries can be traced back to childhood questions. The discovery that the world is bigger than we had imagined happens in many ways, and learning that we have some choices in deciding how new facts, new experiences, and new perspectives can matter to us is a necessary part of education.

When Emotions Flare: Solar Rhythms, Emotions And Cycles Of Political Revolution, Andreas Hernandez, Carolina Zilli Vieira, Alexandra Smith, Rebecca Olson

Geography and Environmental Studies Faculty Publications

Revolutions are among the most transformative events in human history. Analyzing 395 revolutionary episodes from 1900 to 2014, we find that major waves cluster around solar maxima - periods of intensified geomagnetic activity. Drawing on biomedical research linking geomagnetic disturbances to cardiovascular and stress regulation, and thus to emotional states, we propose that solar cycles modulate the affective ecologies within which revolutions arise. Solar activity may accelerate, shape, and amplify revolutionary cycles by heightening emotional climates and tipping fragile systems toward mass mobilization. This reframes revolutions as planetary events - entanglements of political conflict, embodied emotion, and cosmic …

Suntan (And Other Solar Tigonometric Functions), John Adam

Mathematics & Statistics Faculty Publications

Question 1: If I₀ is the solar irradiance (power per unit area, W/m²) reaching my head, express the intensity on the side of my face (I_s) in terms of θ. Assume for now that the irradiance is independent of path length through the atmosphere and that my face is normal to the direction θ = 90°.

Using the 1962 U.S. Standard Atmosphere,² Hottel (1976)³ expressed the solar irradiance using the formula

I = I₀(a₀ + a₁e^{−k sec θ}), where A is the elevation in kilometers and

a₀ = 0.4237 − 0.00821(6 − A)²; a₁ = 0.5055 …

The B³Π–A³Δ And B³Π–X¹Σ+ Band Systems Of Zro, Manish Bhusal, Peter F. Bernath, Jacques Liévin, Léo Lavy

Chemistry & Biochemistry Faculty Publications

The zirconium oxide (ZrO) b³Π–a³Δ system is a prominent source of opacity in the atmospheres of S-type stars in the near-infrared region. The emission spectra of ZrO, obtained at the National Solar Observatory located at Kitt Peak in Arizona, have been utilized to analyze this band system. A reanalysis of the 0–0 vibrational band of the b³Π–a³Δ transition has been carried out. For the first time, the vibrational bands with 1 ⩽ v ′ ⩽ 3 and v″ ≤ 4 for the same electronic transition have been rotationally analyzed using PGOPHER. Additionally, the 0–0 and 1–1 bands of the spin-forbidden …

A Time-Dependent Spectral Analysis Of Γ Cassiopeiae, Sean J. Gunderson, David P. Huenemoerder, José M. Torrejón, Dustin K. Swarm, Joy S. Nichols, Pragati Pradhan, Richard Ignace, Hans Moritz Guenther, A.M.T. Pollock, Norbert S. Schulz

Publications

We investigated the temporal and spectral features of γ Cassiopeiae’s X-ray emission within the context of the white dwarf (WD) accretion hypothesis. We find that the variabilities present in the X-ray data show two different signals, one primarily due to absorption and the other due to flickering like in nonmagnetic cataclysmic variables. We then use this two-component insight to investigate previously unreported simultaneous XMM and NuSTAR data. The results of model fitting find WD properties consistent with optical studies alongside a significant secondary, thermal source. We propose a secondary shock between the Be decretion disk and WD accretion disk as …

On The Evidence For The Violation Of The Equivalence Principle In Disk Galaxies, Corey Sargent, William Clark, Antonia Seifert, Alicia Mand, Emerson Rogers, Adam Lane, Alexandre Deur, Balša Terzić

Physics Faculty Publications

We examine the claimed observations of a gravitational external field effect (EFE) reported by Chae et al. We show that observations suggestive of the EFE can be interpreted without violating Einstein’s equivalence principle, namely from known correlations between the morphology, the environment, and dynamics of galaxies. While Chae et al.’s analysis provides a valuable attempt at a clear test of modified Newtonian dynamics, an evidently important topic, a re-analysis of the observational data does not permit us to confidently assess the presence of an EFE or to distinguish this interpretation from that proposed in this article.

Rapid Inference Of Atmospheric Feature Parameters From Light Curves Using Bayesian Neural Networks, Eugenio A. Diaz

Honors Undergraduate Theses

Mapping atmospheres using rotationally modulated light curves offers insights into cloud structures and dynamics. Current retrieval methods, primarily based on Markov Chain Monte Carlo (MCMC) techniques like Aeolus, can infer atmospheric features but are computationally prohibitive for large datasets. This project proposes a neural network (NN) framework for the rapid, variational inference of atmospheric structure from light curves, particularly those of brown dwarfs. The primary approach focuses on training a Bayesian NN (BNN) to perform regression, predicting the spot parameters that describe the object's surface brightness map. Given the scarcity of suitable observational training data, the BNN is trained on …

Uncertainty In Solar Wind Propagation: An Analysis Of L1 To Earth Variability And The Implications For Geospace Modeling In Space Weather Operations, Espen T. Fredrick

Physics Dissertations - Archive

As humanity's technological dependence grows, so does its vulnerability to space weather. Space weather describes solar-driven phenomena in the near-Earth space environment and their terrestrial effects. Many of these effects occur due to the interaction of the solar wind and Earth's magnetosphere. The solar wind originates at the solar corona and carries solar plasma and magnetic field outward through the solar system. This magnetic field, known as the interplanetary magnetic field (IMF) during transit, can undergo magnetic reconnection with Earth's geomagnetic field when oppositely aligned field lines converge. This process transfers energy into Earth's magnetosphere, driving space weather phenomena.

Space …

Characterizing The Earth's Magnetosheath With In Situ Measurements, Hector A. Salinas

Physics Dissertations - Archive

Earth’s magnetosheath is a region of shocked plasma that mediates energy and momentum transfer from the solar wind to the magnetosphere. The dynamics and thus the plasma structures of this region are highly dependent on upstream solar wind conditions. As such, the region is often characterized as a turbulent environment, with the most intense periods of turbulence occurring often under quasi-parallel bow shock conditions. This magnetosheath turbulence displays as variable and large-scale fluctuations with in-situ measurements. Given that turbulence is a characteristic feature of the magnetosheath, this dissertation asks two questions: (1) How are plasma structures inside the sheath affected …