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Articles 31 - 60 of 118
Full-Text Articles in Physical Sciences and Mathematics
The Impact Of Initial Abundances On Modeling The Weak S-Process, Lev S. Serxner
The Impact Of Initial Abundances On Modeling The Weak S-Process, Lev S. Serxner
Macalester Journal of Physics and Astronomy
No abstract provided.
The Survey Of Hi In Extremely Low-Mass Dwarfs: New Results From Vla Imaging, Francesco Pecere, John M. Cannon, Damen Beverlin, Jackson Codd
The Survey Of Hi In Extremely Low-Mass Dwarfs: New Results From Vla Imaging, Francesco Pecere, John M. Cannon, Damen Beverlin, Jackson Codd
Macalester Journal of Physics and Astronomy
We present new HI spectral line imaging of 19 galaxies in the “Survey of HI in Extremely Low-mass Dwarfs” (SHIELD) acquired for Large Program VLA/ 20A-330. Using the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array (VLA) in the C configuration, we produce images of the neutral interstellar medium (HI) on angular scales of 15 to 20 arcseconds (corresponding to physical resolutions of 200 to 1100 parsecs). The three-dimensional cubes probe the morphology and kinematics of the gas at a range of spatial and spectral resolutions. The cubes were collapsed to produce two-dimensional moment maps (representing HI mass …
Hunting For Fast Radio Bursts From Messier 82: Exploring The Frb--Magnetar Connection, Susie Paine
Hunting For Fast Radio Bursts From Messier 82: Exploring The Frb--Magnetar Connection, Susie Paine
Macalester Journal of Physics and Astronomy
Fast radio bursts (FRBs) are short-duration radio pulses of cosmological origin. Among the most common sources predicted to explain this phenomenon are bright pulses from a class of extremely highly magnetized neutron stars known as magnetars. In 2020, a Galactic magnetar produced an FRB-like burst, allowing researchers to constrain the Galactic magnetar burst rate. We assume that the magnetar burst rate scales with star formation rate and test an important prediction for similar bursts in nearby galaxies. Messier 82 (M82) has a star formation rate 40 times that of the Milky Way, implying that the magnetar burst rate would be …
Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma
Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma
Macalester Journal of Physics and Astronomy
The Finite-Difference-Time-Domain (FDTD) method is a numerical method that calculates electric fields or magnetic fields by interleaving them in space and time. Using a python package called “MEEP”, I was able to write optical simulations of ultrafast experiments, especially the Terahertz Pump-Probe experiments. The goal of this project was to use FDTD simulation to measure the transmission of an electro-magnetic pulse passing through a thin film of conducting material on a dielectric substrate in order to study the characteristic conductivity of potential solar cell materials.
Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li
Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li
Macalester Journal of Physics and Astronomy
We present a molecular line search in spectral imaging of the elliptical galaxy M87 using archival data from the Atacama Large Millimeter/sub-millimeter Array (ALMA). The primary goal of this project is to verify and characterize possible CO transition lines, which can be used for future studies to determine the dynamics of the system, or the mass of the supermassive black hole (BH) in the center of the galaxy. After performing extensive atmospheric modeling, we found that most of the absorption features have a corresponding atmospheric ozone transition, so it is unlikely that these features are either Galactic or extragalactic. We …
Lie Algebras And The Poincare Group, Jack Hempel Costello
Lie Algebras And The Poincare Group, Jack Hempel Costello
Macalester Journal of Physics and Astronomy
This paper will discuss my research with
Professor Tonnis ter Veldhuis on the Poincare Group
and other similar algebraic approaches based on the
Minkowski Metric. This paper will begin with an
introduction discussing group theory and expand on its
specific applications in theoretical physics.
Simulating Interactions Between Coronal Mass Ejections, Damen S. Beverlin, Tatiana Niembro
Simulating Interactions Between Coronal Mass Ejections, Damen S. Beverlin, Tatiana Niembro
Macalester Journal of Physics and Astronomy
Coronal mass ejections (CMEs) launch large amounts of plasma and magnetic fields into the interplanetary medium. Under the right initial conditions, this ejecta can reach Earth and cause issues with electronic devices. As such, we would like to have an accurate model that depicts how these CMEs propagate as they leave the sun. By using fluid dynamics and one-minute resolution in-situ solar wind data, we sought to simulate CME plasma propagation with analytical and numerical models. Because the interstellar medium contains other material and other events happen on the sun simultaneously, CMEs can interact with each other and other ejecta, …
Custom Calibration And Correction Of Photoemission Electron Microscope Images Using Graphene, Henry Bell
Custom Calibration And Correction Of Photoemission Electron Microscope Images Using Graphene, Henry Bell
Macalester Journal of Physics and Astronomy
The Photoemission Electron Microscope (PEEM) is a full-field electron microscope that utilizes the photoelectric effect to image a surface. Due to a spatial resolution on the order of 10 nanometers and its ability to image both the morphology of a surface and its band structure, it is a useful tool for understanding the properties of materials for use in electronic devices. To correct for random sample misalignment and the experimental frame of reference in the spectroscopy mode of the PEEM, the 3D dataset must be rotated in both the momentum and energy coordinates which requires pixel calibration and energy alignment. …
Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal
Macalester Journal of Physics and Astronomy
With last year’s commitment to all in-state sales of new passenger cars and trucks being zero-emission by 2035 (California Executive Order N-79-20), California is leading the charge for transportation electrification in the United States. Despite being at the forefront of climate change management and mitigation, California has some of the worst air quality in the nation. While primarily motivated by a desire to reduce carbon dioxide emissions and reliance on fossil fuels, transportation electrification will also have a significant impact on local air quality. The goal of this study is to quantify and qualify this impact in the context of …
Sampling Candidate Reionization Galaxies Using Spectral Energy Distribution Fitting, Nicholas J. Velikonja, Michael Rutkowski
Sampling Candidate Reionization Galaxies Using Spectral Energy Distribution Fitting, Nicholas J. Velikonja, Michael Rutkowski
Macalester Journal of Physics and Astronomy
The process of reionization is one of the major pieces of galaxy evolution which remain to be un- derstood. With new observational tools like JWST on the horizon, imaging reionization-era galaxies will soon be possible. However, because the ionizing radiation is absorbed by the neutral hydrogen it ionizes, observers need some other parameter by which to identify those galaxies capable of reionizing. The search for ionizing emission via related parameters is well underway, and has come up with some tentative correlations, yet a consistent indicator or set of indicators remains to be discovered. New data in the Low-Redshift Lyman Continuum …
Laser-Excitation Spectroscopy Of Niobium Hydride And Tantalum Hydride, Siddhant Singh
Laser-Excitation Spectroscopy Of Niobium Hydride And Tantalum Hydride, Siddhant Singh
Macalester Journal of Physics and Astronomy
The experimental results presented in this paper shed light on some of the fundamental bonding characteristics of NbH and TaH. Six bands of niobium hydride and five weak bands of tantalum hydride were observed for the first time using laser excitation spectroscopy. The rotational assignments of observed bands were confirmed using dispersed fluorescence experiments for NbH and by checking the internal consistency of a global least squares fit for the weaker bands of TaH. For TaH, we were able to determine the term energies and molecular constants of each of its observed states to a high degree of accuracy …
Carrier Lifetime And Carrier Mobility Of Gaasn With Changing Nitrogen Concentration, Sun Gyu Park
Carrier Lifetime And Carrier Mobility Of Gaasn With Changing Nitrogen Concentration, Sun Gyu Park
Macalester Journal of Physics and Astronomy
In this work, we conducted Ultrafast Conductivity Measurements, using THz Spectroscopy to characterize the carrier mobility and the carrier lifetime of gallium arsenide nitride (GaAsN) thin films with a range of Nitrogen concentrations. The photoexcitation of semiconductor samples excites free charges by promoting electrons from the valence band to the conduction band. We then measure the change in conductivity by measuring the transmission of a THz electromagnetic pulse after photoexcitation and comparing with the signal that was measured without photoexcitation. The values of transmission are then converted into conductivity, from which we derive the carrier concentration and scattering time of …
Automatic Leptonic Tensor Generation For Beyond The Standard Model (Bsm) Theories, Diego F. Lopez Gutierrez
Automatic Leptonic Tensor Generation For Beyond The Standard Model (Bsm) Theories, Diego F. Lopez Gutierrez
Macalester Journal of Physics and Astronomy
With the development of the Deep Underground Neutrino Experiment (DUNE) and Tokai-to-Hyper-Kamiokande (T2HK), we are entering the era of high-precision neutrino measurements. The colossal output of data from DUNE, plus the current data from several other neutrino experiments, will require a fast and efficient method of testing our BSM models in event generators. However, current methods for implementing a BSM theory in the event generators are prone to errors and time-consuming. We propose a novel program capable of automatically calculating the leptonic tensor for a given quantum field theory Lagrangian. This program is written in Python and utilizes the Universal …
Model Of Electromagnetic Waves In An Axion-Induced Parity Symmetry Violation, Sarah Lipstone
Model Of Electromagnetic Waves In An Axion-Induced Parity Symmetry Violation, Sarah Lipstone
Macalester Journal of Physics and Astronomy
Axion particles have been postulated to resolve the strong CP problem in Quantum chromodynamics. The axion field may double as the inflaton field that produces cosmic inflation. In this project, we use a combination of analytical and numerical analysis to study how axion-induced parity symmetry violation affects the dynamics of electromagnetic waves.
Renewing The Paradigm: Simulating The Miso Region Electrical Grid Using Renewable Energy Generation With Implementation Of Long-Term Hydrogen Storage, Jackson C. Henningfield
Renewing The Paradigm: Simulating The Miso Region Electrical Grid Using Renewable Energy Generation With Implementation Of Long-Term Hydrogen Storage, Jackson C. Henningfield
Macalester Journal of Physics and Astronomy
The current electrical grid regime is not optimized to include renewable sources of power generation such as wind and solar. Electrical storage, as of now, is primarily established through the short-term generation and demand-meeting consumption leaving much of the grid susceptible to inefficiencies and power loss during natural events that leave grids out of commission. Delineating a new type of long-term storage, a hydrogen fuel cell, would ensure a reliable source of power to the masses regardless of the physical and climatic geography. The MISO region provides a perfect case study to introduce the ideas of diverse energy generation and …
Electrical Grid Energy Storage Using Hydrogen: A Feasibility Study, Elizabeth M. Curtiss
Electrical Grid Energy Storage Using Hydrogen: A Feasibility Study, Elizabeth M. Curtiss
Macalester Journal of Physics and Astronomy
In this project, we studied the possibility of implementing hydrogen as energy storage. With the focus being on decarbonizing the grid, we looked at studies that were powered by renewable sources. In addition to utilizing renewable sources, we decided to study electrolysis as a way to produce hydrogen. Electrolysis is the splitting of water to obtain hydrogen and oxygen, which is a carbon free technique. Pulling from two different papers, we were able to construct an equation that modeled the levelized cost of producing hydrogen. We also calculated the levelized cost of a fuel cell too, with hydrogen as fuel. …
Particle Dynamics From The Method Of Nonlinear Realizations And Maxwell Group, Daniel S. Clark
Particle Dynamics From The Method Of Nonlinear Realizations And Maxwell Group, Daniel S. Clark
Macalester Journal of Physics and Astronomy
Professor Tonnis ter Veldhuis provides Macalester students with research opportunities in theoretical physics. In the Summer of 2020, a team of three students were introduced to the method of nonlinear realization of symmetries by studying Prof. Veldhuis’s prior research regarding an application of the method to membrane dynamics (1). Subsequent developments of this prior work involved research into torsion and riemann curvature tensors, as well as metric compatibility, highlighting the connection between symmetry and space-time structure. The foundation of this work was the D=4 Poincare algebra in the D=3 Lorentz group covariant form. After this introduction, each team member developed …
Virtual Prototyping Of Liquid Lithium Divertor Concepts, Brennan Arnold
Virtual Prototyping Of Liquid Lithium Divertor Concepts, Brennan Arnold
Macalester Journal of Physics and Astronomy
A tokamak divertor must withstand power deposition in excess of 10 MW/m^2 in steady state and much higher in disruptions, enough to destroy nearly any material. In order to handle this extreme heat, there is some interest in using liquid metal flows to continually renew the divertor surface. In this paper, we examine an idea for a divertor with a porous surface that allows liquid lithium flowing through the divertor to percolate to the plasma facing surface. This idea is complicated by magnetohydrodynamic drag, where the stong magnetic fields in the tokamak cause the lithium to flow too slowly to …
Modeling Gyrating Motion Using Mathematica, Jonathan Alvarado-Gomez
Modeling Gyrating Motion Using Mathematica, Jonathan Alvarado-Gomez
Macalester Journal of Physics and Astronomy
In this report I will describe a method of creating animations of gyrating objects in Mathematica [4]. There are 4 inputs to a function called trajectory, which are a time step, maximum time duration, initial force vector, and a 3x3 matrix that represents a tensor for the gyration of the object. I utilized the computer program Mathematica [4] to create 3D images of a gyrating object in the object frame of view. A collection of these images were put together in order to make an animation, which can be used as a tool for future researchers to investigate interesting paths …
Supercdms: Energy Calibration Of A Ge Hv Particle Detector, Salamong Xiong, Vuk Mandic, Matthew Fritts, Nicholas Mast, Jacob Nelson
Supercdms: Energy Calibration Of A Ge Hv Particle Detector, Salamong Xiong, Vuk Mandic, Matthew Fritts, Nicholas Mast, Jacob Nelson
Macalester Journal of Physics and Astronomy
The goal of the SuperCDMS collaboration is to directly detect dark matter. Weakly Interacting Massive Particles (WIMPs) are potential candidates. To detect WIMPs, it is important to be able to predict how a Ge/Si particle detector will respond to a dark matter signal. In particular, it is necessary to calibrate the recoil energy measured by these detectors. This paper presents evidence for dark matter, a description of the detector operation, and procedures used to analyze measured data from a SuperCDMS-HV Ge particle detector using Am-241 and a PuBe neutron source. Due to high event rate, criteria were developed to remove …
Calculating Centrality Variables And Geometric Quantities Associated With High Energy Pb+Pb And Au+Au Collisions Using A Monte Carlo Glauber Model, Anya Wolterman
Macalester Journal of Physics and Astronomy
The Glauber model provides insight into the initial state of nuclear collisions by treating them in terms of the interactions between their constituent nucleons, in accordance with theories about the scattering of composite particles. These phenomenological techniques are commonly used to determine various geometric quantities associated with such complex, femtoscopic many-body systems. The Monte Carlo Glauber approach uses a random impact parameter and measured nuclear densities to investigate quantifiable properties like particle multiplicity and average geometric eccentricity for heavy ion collisions. The former involves incorporating a particle production model to plot the total transverse energy or the number of particles …
Fabrication Of Nanoscale Columnar Diodes By Glancing Angle Deposition, Jacob D. Weightman
Fabrication Of Nanoscale Columnar Diodes By Glancing Angle Deposition, Jacob D. Weightman
Macalester Journal of Physics and Astronomy
Glancing angle deposition (GLAD) is a process in which thin films are deposited onto a substrate with obliquely incident vapor together with precisely controlled azimuthal substrate rotation. Ballistic shadowing effects due to the oblique incidence produce nanoscale structures, and a variety of feature shapes, including tilted columns, helices, and vertical columns can be achieved by varying the azimuthal rotation during the deposition process. Due to this control of morphology and the compatibility of the process with a wide variety of materials, GLAD films have found applications in a variety of fields including sensing, photonics, photovoltaics, and catalysis, where they are …
Nitrogen Vacancy Center Optical Magnetometry Of A Barium-Iron-Cobalt Superconductor, William Setterberg
Nitrogen Vacancy Center Optical Magnetometry Of A Barium-Iron-Cobalt Superconductor, William Setterberg
Macalester Journal of Physics and Astronomy
Experimentally probing the intrinsic properties of superconductors—such as the London penetration depth λ and the critical fields Hc1 and Hc2—poses a difficult task. Various sample- and measurement-related factors can impact the efficacy of results obtained for λ or Hc1, such as perturbations to the magnetic properties of a superconducting sample or crystalline defects. One measurement technique that can minimize the impact of both of these issues is known as Nitrogen Vacancy (NV) center magnetometry. In this work, we use NV center magnetometry to perform minimally-invasive measurements of the lower critical field Hc1 and the …
The Leoncino Dwarf: A Neutral Hydrogen Analysis Of Agc 198691 And Its Extremely Metal-Poor Environment, Tylyn Page
The Leoncino Dwarf: A Neutral Hydrogen Analysis Of Agc 198691 And Its Extremely Metal-Poor Environment, Tylyn Page
Macalester Journal of Physics and Astronomy
Studies of low-mass galaxies are important for populating the low-mass ends of funda- mental physical relations. Extremely metal-poor (XMP) galaxies are low-mass galaxies with gas-phase oxygen abundances of 12+log(O/H) ≤ 7.35 ( 1/20 Z⊙), and are especially interesting as proxies for studying the distant past, as their chemical makeup resembles those of galaxies in the early universe. AGC 198691, referred to as the Leoncino Dwarf, was discovered through the Arecibo Legacy Fast ALFA (ALFALFA) survey and found to have an oxygen abundance of less than 3% Z⊙. Presented here are the results of recent Karl G. Jansky Very Large Array …
Large Scale Grid Integration Of Wind And Solar Power With Storage, Nicholas Moore
Large Scale Grid Integration Of Wind And Solar Power With Storage, Nicholas Moore
Macalester Journal of Physics and Astronomy
The current energy grid in the United States is dominated by carbon intense energy generation methods that are based on production when and where it is required. However, solar and wind power have proved themselves as the most promising carbon free energy generation sources. Due to the unpredictable and uncontrollable nature of energy production from solar and wind, large scale integration of these resources into the electric grid will require robust storage capacity. In this project, we model the energy grid of the Midcontinent Independent System Operator (MISO) energy region with high concentrations of solar and wind power to analyze …
Probing The Magnetic Fields In Cosmic Web Filaments, Andrew L. Mizener
Probing The Magnetic Fields In Cosmic Web Filaments, Andrew L. Mizener
Macalester Journal of Physics and Astronomy
We present a project to constrain the properties of magnetic fields in Cosmic Web filaments. We first perform rotation measure (RM) synthesis on 24 S-band Karl G Jansky Very Large Array (VLA) observations of moderate-redshift active galactic nuclei (AGN). These observations are combined with an existing catalog of Cosmic Web filaments in order to determine the number of filaments a given sight-line passes near or through. By tracking how observables such as rotation measure and polarization fraction change as a function of the number of intervening cosmic web filaments, we take the first steps towards providing observational constraints on the …
Shape Model Of Potentially Hazardous Asteroid 1981 Midas From Radar And Lightcurve Observations, Riley Mcglasson
Shape Model Of Potentially Hazardous Asteroid 1981 Midas From Radar And Lightcurve Observations, Riley Mcglasson
Macalester Journal of Physics and Astronomy
We report observations of potentially hazardous, Apollo-class asteroid 1981 Midas, which passed 0.090 au from Earth (35 lunar distances) on March 21, 2018. During this close approach, Midas was observed by radar both from the Arecibo Observatory on March 21 through 25 (five nights), and from NASA's Goldstone Deep Space Communications Complex on March 19 and 21. These radar observations yielded one-dimensional continuous-wave spectra and two-dimensional delay-Doppler images. In addition, there have been optical lightcurve observations of Midas during four apparitions (1987, 1992, 2004, and 2018), which showed a rotation period of 5.22 hours. Midas has an absolute magnitude of …
Deposition Of Tin For Battery And Supercapacitor Electrodes For Energy Storage, Kieran M. Liming
Deposition Of Tin For Battery And Supercapacitor Electrodes For Energy Storage, Kieran M. Liming
Macalester Journal of Physics and Astronomy
Titanium Nitride (TiN) can be sputtered into a thin film, and is a promising component for battery and supercapacitor electrodes. This research explored the relationship between Nitride partial pressure and film characteristics. We sputtered TiN into thin films in a low vacuum environment at tempuratures of approximately 70o C. Most films were deposited over the course of one hour including a five minute presputtering period where the substrate was covered. We found that film thickness, system voltage, and film restivitiy to be a function of N2 partial pressure.
Searching For Doublet Vectorlike Leptons Using The Atlas Particle Detector, Brynn Keller
Searching For Doublet Vectorlike Leptons Using The Atlas Particle Detector, Brynn Keller
Macalester Journal of Physics and Astronomy
Vectorlike leptons are a simple extension of the standard model, akin to a fourth family of leptons. This paper describes aspects of the preparation for a search for VLLs at an ATLAS particle collider. During this research, signal and control regions were determined with use of a Monte Carlo simulation in order to best estimate where to measure different kinds of background and where to search for a potential signal. These signal and control regions were optimized with respect to MET, LT, and number of light and heavy leptons with a goal of a 95\% confidence limit.
A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan
A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan
Macalester Journal of Physics and Astronomy
We present observations from two separate methods for observing the Galactic Center in an attempt to characterize its pulsar and neutron star populations. A persistent puzzle of the past 20 years has been the lack of pulsar detections towards the Galactic Center, specifically within a few parsecs of the central supermassive black hole Sgr A*. This object is bright in the total intensity of its polarized emission, but is very weakly linearly polarized. We take advantage of these circumstances in an experimental search technique where we utilize the Faraday effect in an attempt to detect high rotation measure (RM) point …