Astrophysics and Astronomy Commons^™

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 …

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 …

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.

Reflectance Spectroscopy Datasets For The Validation Of Tanager, Kristiana Lapo, Kathleen Hoza, Sammy Theuer, Melissa S. Rice

Geology Faculty Publications

The Three-Axis N-sample Automated Goniometer for Evaluating Reflectance (TANAGER) is a custom goniometer designed to rapidly acquire spectra of natural rock surfaces across the full scattering hemisphere. TANAGER interfaces with a Malvern Panalytical ASD Fieldspec 4 Hi-Res reflectance spectrometer to collect data from 350-2500 nm at a range of incidence, emission and azimuth angles. To validate the accuracy and repeatability of data collected with TANAGER - and to characterize any instrument noise, artifacts or sample heating effects - we collected spectra from three categories of targets: (1) powdered calcium sulfate (anhydrite), (2) naturally weathered basalt surfaces, and (3) color calibration …

Moid Using New Sets Of Universal Functions, Ayman Homda, Hany R. Dwidar, Abdelaziz A. Bakry, M.N. Mohamad Ismail, Ahmed El-Raffie

Al-Azhar Bulletin of Science

In this paper, based on Goodyear's time transformation formula, we used a set of modified universal functions to construct the minimum distance function between any two celestial objects. We determined the distance between objects in space under a specific time constraint. We used the continued fractions method for quick convergence of the distance function. We used the inverse series to obtain a first initial guess to solve the convergence equation. Furthermore, the Lagrange multiplier method was used to determine the minimum distance between the two objects under the specified time constraint. We constructed an algorithm and applied it with the …

Automated Identification And Mapping Of Interesting Mineral Spectra In Crism Images, Arun M. Saranathan

Doctoral Dissertations

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) has proven to be an invaluable tool for the mineralogical analysis of the Martian surface. It has been crucial in identifying and mapping the spatial extents of various minerals. Primarily, the identification and mapping of these mineral spectral-shapes have been performed manually. Given the size of the CRISM image dataset, manual analysis of the full dataset would be arduous/infeasible. This dissertation attempts to address this issue by describing an (machine learning based) automated processing pipeline for CRISM data that can be used to identify and map the unique mineral signatures present in …

Toltec: A New Multichroic Imaging Polarimeter For The Large Millimeter Telescope, Nat S. Denigris

Doctoral Dissertations

The TolTEC camera is a new millimeter-wave imaging polarimeter designed to fill the focal plane of the 50-m diameter Large Millimeter Telescope (LMT). Combined with the LMT, TolTEC offers high angular resolution (5", 6.3", 9.5") for simultaneous, polarization-sensitive observations in its three wavelength bands: 1.1, 1.4, and 2.0 mm. Additionally, TolTEC is designed to reach groundbreaking mapping speeds in excess of 1 deg²/mJy²/hr, which will enable the completion of deep surveys of large-scale structure, galaxy evolution, and star formation that are currently limited when considering practical observation times for other ground-based observatories. This thesis covers the …

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 …

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 …

Density And Magnetic Field Asymmetric Kelvin‐Helmholtz Instability, Xuanye Ma, Peter Delamere, Katariina Nykyri, Antonius Otto, Stefan Eriksson, Lihui Chai, Brandon Burkholder, Andrew Dimmock, Yu-Lun Liou, Shiva Kavosi

Publications

The Kelvin‐Helmholtz (KH) instability can transport mass, momentum, magnetic flux, and energy between the magnetosheath and magnetosphere, which plays an important role in the solar‐wind‐ magnetosphere coupling process for different planets. Meanwhile, strong density and magnetic field asymmetry are often present between the magnetosheath (MSH) and magnetosphere (MSP), which could affect the transport processes driven by the KH instability. Our magnetohydrodynamics simulation shows that the KH growth rate is insensitive to the density ratio between the MSP and the MSH in the compressible regime, which is different than the prediction from linear incompressible theory. When the interplanetary magnetic field (IMF) …

Adsorption Of Crystal Violet Dye From Synthetic Wastewater By Ball-Milled Royal Palm Leaf Sheath, Neloy Sen, Nawrin Rahman Shefa, Kismot Reza, Sk Md Ali Zaker Shawon, Md. Wasikur Rahman

Physics and Astronomy Faculty Publications and Presentations

The current study shows that using a batch approach to remove crystal violet dye from synthetic wastewater is feasible when using royal palm leaf sheath powder as an adsorbent. In order to investigate the effects of many parameters, including starting concentration, pH effect, dye concentration, adsorbent dose, contact time, and temperature, experiments were carried out under various operating conditions. Maximum removal was obtained at pH 6 and at a concentration of 100 ppm, which are considered as ideal values. The influence of pH and dye concentration was shown to be substantial. Langmuir, Freundlich, and Temkin isotherm models were fitted to …

On Skew-Symmetric Splitting And Entropy Conservation Schemes For The Euler Equations, Björn Sjögreen, H.C. Yee

United States National Aeronautics and Space Administration: Publications

The Tadmor type of entropy conservation formulation for the Euler equations and various skew-symmetric splittings of the inviscid flux derivatives are discussed. Numerical stability of high order central and Padé type (centered compact) spatial discretization is enhanced through the application of these formulations. Numerical test on a 2-D vortex convection problem indicates that the stability and accuracy of these formulations using the same high order central spatial discretization are similar for vortex travel up to a few periods. For two to three times longer time integrations, their corresponding stability and accuracy behaviors are very different. The goal of this work …

Strongly Magnetized Accretion In Two Ultracompact Binary Systems, Thomas J. Maccarone, Thomas Kupfer, Edgar Najera Casarrubias, Liliana E. Rivera Sandoval, Aarran W. Shaw, Christoper T. Britt, Jan Van Roestel, David R. Zurek

Physics and Astronomy Faculty Publications and Presentations

We present the discoveries of two of AM CVn systems, Gaia14aae and SDSS J080449.49+161624.8, which show X-ray pulsations at their orbital periods, indicative of magnetically collimated accretion. Both also show indications of higher rates of mass transfer relative to the expectations from binary evolution driven purely by gravitational radiation, based on existing optical data for Gaia14aae, which show a hotter white dwarf temperature than expected from standard evolutionary models, and X-ray data for SDSS J080449.49+161624.8 which show a luminosity 10−100 times higher than those for other AM CVn at similar orbital periods. The higher mass transfer rates could be driven …

Powerful Radio Sources In The Southern Sky. Iii. First Results Of The Optical Spectroscopic Campaign, A. García-Pérez, H. A. Peña-Herazo, A. Jimenez-Gallardo, V. Chavushyan, F. Massaro, S. V. White, A. Capetti, B. Balmaverde, W. R. Forman, Juan P. Madrid

Physics and Astronomy Faculty Publications and Presentations

We recently built the G4Jy-3CRE catalog of extragalactic radio sources. This catalog lists 264 powerful radio sources selected with similar criteria to those of the revised Third Cambridge Catalog, but visible from the Southern Hemisphere. A literature search revealed that 119 sources in the G4Jy-3CRE catalog (i.e., 45%) lack a firm spectroscopic redshift measurement. Here, we present a campaign aimed at acquiring optical spectra of G4Jy-3CRE sources and measuring their redshifts. We used single-slit observations obtained with the Víctor Blanco Telescope, the New Technology Telescope, the Southern Astrophysical Research Telescope, and the 2.1 m telescope of the Observatorio Astronómico Nacional …

Roaring To Softly Whispering: X-Ray Emission After ∼3.7 Yr At The Location Of The Transient At2018cow And Implications For Accretion-Powered Scenarios, Giulia Migliori, R. Margutti, B. D. Metzger, R. Chornock, C. Vignali, D. Brethauer, Liliana E. Rivera Sandoval, J. S. Bright, T. Laskar, D. Milisavljevic

Physics and Astronomy Faculty Publications and Presentations

We present the first deep X-ray observations of luminous fast blue optical transient (LFBOT) AT 2018cow at ∼3.7 yr since discovery, together with the reanalysis of the observation at δt ∼ 220 days. X-ray emission is significantly detected at a location consistent with AT 2018cow. The very soft X-ray spectrum and sustained luminosity are distinct from the spectral and temporal behavior of the LFBOT in the first ∼100 days and would possibly signal the emergence of a new emission component, although a robust association with AT 2018cow can only be claimed at δt ∼ 220 days, while at …

Research Experiences Via Integrating Simulations And Experiments (Revise): A Model Collaborative Research Project For Undergraduate Students In Co2 Sorbent Design, Anthony Griffin, Neziah Smith, Mark Robertson, Bianca Nunez, Jacob Mccraw, Haoyuan Chen, Zhe Qiang

Physics and Astronomy Faculty Publications and Presentations

Undergraduate research experiences are an instrumental component of student development, increasing conceptual understanding, promoting inquiry-based learning, and guiding potential career aspirations. Moving one step further, as research continues to become more interdisciplinary, there exists potential to accelerate student growth by granting additional perspectives through collaborative research. This study demonstrates the utilization of a model collaborative research project, specifically investigating the development of sorbent technologies for efficient CO2 capture, which is an important research area for improving environmental sustainability. A model CO2 sorbent system of heteroatom-doped porous carbon is utilized to enable students to gain knowledge of adsorption processes, through combined …

Swarm Intelligence Methods For Extreme Mass Ratio Inspiral Search: First Application Of Particle Swarm Optimization, Xiao-Bo Zou, Soumya D. Mohanty, Hong-Gang Luo, Yu-Xiao Liu

Physics and Astronomy Faculty Publications and Presentations

Swarm intelligence (SI) methods are nature-inspired metaheuristics for global optimization that exploit a coordinated stochastic search strategy by a group of agents. Particle swarm optimization (PSO) is an established SI method that has been applied successfully to the optimization of rugged high-dimensional likelihood functions, a problem that represents the main bottleneck across a variety of gravitational wave (GW) data analysis challenges. We present results from the first application of PSO to one of the most difficult of these challenges, namely the search for the Extreme Mass Ratio Inspiral (EMRI) in data from future spaceborne GW detectors such as LISA, Taiji, …

There Is Life On Mars, Colin M. Johnston, Olivier B. Cohen

CAFE Symposium 2024

An extensive research project that involved the research of multiple major experiments and discoveries about possible life on the planet Mars. Facts, Data, conspiracies and theories have all been taken into account and provided in this project.

Axion-Polaritons In Quark Stars: A Possible Solution To The Missing Pulsar Problem, Efrain J. Ferrer, Vivian De La Incera

Physics and Astronomy Faculty Publications and Presentations

This paper proposes an alternative mechanism to solve the so-called missing pulsar problem, a standing paradox between the theoretical expectations about the number of pulsars that should exist in the galaxy center of the Milky Way and their absence in the observations. The mechanism is based on the transformation of incident γ rays into hybridized modes, known as axion-polaritons, which can exist inside highly magnetized quark stars with a quark matter phase known as the magnetic dual chiral density wave phase. This phase, which is favored over several other dense matter phases candidates at densities a few times nuclear saturation …