Astrophysics and Astronomy Commons^™

Probing The Physical Mechanisms Responsible For Brown Dwarf And Giant Planet Formation, Sarah Betti

Doctoral Dissertations

The disks that form around young stellar objects provide the essential material for their continued growth as well as the formation of planets, making them ideal laboratories to investigate the mechanisms and environments key for substellar and planetary formation. In this dissertation, I explore two main formation processes: the transportation of water necessary for giant planet formation, and the accretion and growth of young brown dwarfs.

First, I study the water ice content in the circumstellar disk of AB Aurigae, a young Herbig Ae star. I detect and map icy grains on the disk surface using high contrast observations taken …

First Approximation Of Population Distributions On The International Space Station, Justin St. P. Walsh, Rao Hamza Ali, Alice C. Gorman, Amir Kanan Kashefi

Art Faculty Articles and Research

This paper presents an analysis of data derived from thousands of publicly available photographs showing life on the International Space Station (ISS) between 2000 and 2020. Our analysis uses crew and locational information from the photographs’ metadata to identify the distribution of different population groups—by gender, nationality, and space agency affiliation—across modules of the ISS, for the first time. Given the significance of the ISS as the most intensively inhabited space habitat to date, an international cooperative initiative involving 26 countries and five space agencies, and one of the most expensive building projects ever undertaken by humans, developing an understanding …

An Introduction To The Veritas Observatory, Alexander Biddle, Ian Kuhl, Jingze (Justin) Zhou, Avery Archer

Annual Student Research Poster Session

Located at the base of Mount Hopkins, Arizona, at an elevation of approximately 4200 feet, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a ground-based gamma ray observatory containing four Cherenkov telescopes designed to detect very high energy gamma rays with energies ranging from 100GeV to 10TeV using the Imaging Atmospheric Cherenkov Technique. In April 2007, VERITAS began successful operations with all four telescopes. As of today, over 15 years of data has been taken by the VERITAS array, stored in an archive of data, and used for a wide variety of research, publications, PhD theses, and conventions …

Analysis Of The Crab Nebula And Pulsar, Alexander Biddle, Ian Kuhl, Jingze (Justin) Zhou, Avery Archer

Annual Student Research Poster Session

Although the Crab Nebula is well understood, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) still regularly observes the Crab's highest energy emissions. These emissions are used to calibrate the telescopes, further, document the system, and investigate the validity of physical models. Our research this summer is geared to analyze data from 2018-2022 to add to an ongoing research project investigating the long term variability of the Crab Nebula’s emission.

The Gbt Diffuse Ionized Gas Survey (Gdigs): Discrete Sources, Dylan J. Linville, Matteo Luisi, Bin Liu, T. M. Bania, Dana S. Balser, Trey V. Wenger, L. M. Haffner

Publications

The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by observing radio recombination line (RRL) emission from 4–8 GHz. The nominal survey zone is 32.3◦ > ℓ > −5◦, | b | < 0.5◦. Here, we analyze GDIGS Hnα ionized gas emission toward discrete sources. Using GDIGS data, we identify the velocity of 35 H II regions that have multiple detected RRL velocity components. We identify and characterize RRL emission from 88 H II regions that previously lacked measured ionized gas velocities. We also identify and characterize RRL emission from eight locations that appear to be previously-unidentified H II regions and 30 locations of RRL emission that do not appear to be H II regions based on their lack of mid-infrared emission. This latter group may be a compact component of the Galactic Diffuse Ionized Gas (DIG). There are an additional 10 discrete sources that have anomalously high RRL velocities for their locations in the Galactic plane. We compare these objects’ RRL data to 13CO, H I and mid-infrared data, and find that these sources do not have the expected 24 µm emission characteristic of H II regions. Based on this comparison we do not think these objects are H II regions, but we are unable to classify them as a known type of object.

A Review On Antibacterial Activity Of Nanoparticles, Badr-Edine Sadoq, Mohammed Reda Britel, Adel Bouajaj, Ramzi Maâlej, Ahmed Touhami, Marwa Abid, Hanen Douiri, Fakhita Touhami, Amal Maurady

Physics and Astronomy Faculty Publications and Presentations

The increasing resistance of bacteria to antibiotic agents is a main global public health problem. The use of nanoparticles is one of the promising ways to overcome microbial resistance to antimicrobial agents. Metal nanoparticles are increasingly used to target bacterial strains. Advances in nanotechnology, in particular the ability to synthesize nanoparticles of specific size and shape, are likely to lead to the development of new antibacterial agents. The antibacterial activities of nanoparticles are largely influenced by their sizes and large surface area/mass ratio. The antibacterial mechanisms of nanoparticles are poorly understood, but the currently accepted mechanisms include oxidative stress induction, …

Search For Subsolar-Mass Black Hole Binaries In The Second Part Of Advanced Ligo’S And Advanced Virgo’S Third Observing Run, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We describe a search for gravitational waves from compact binaries with at least one component with mass 0.2 –1.0M⊙ and mass ratio q ≥ 0.1 in Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and Advanced Virgo data collected between 2019 November 1, 15:00 UTC and 2020 March 27, 17:00 UTC. No signals were detected. The most significant candidate has a false alarm rate of 0.2yr−1 ⁠. We estimate the sensitivity of our search over the entirety of Advanced LIGO’s and Advanced Virgo’s third observing run, and present the most stringent limits to date on the merger rate of binary black holes …

Effects Of Spin-Orbit Coupling On Gravitational Waveforms From A Triaxial Non-Aligned Neutron Star In A Binary System, Wen-Fan Feng, Tan Liu, Jie-Wen Che, Yan Wang, Soumya D. Mohanty

Physics and Astronomy Faculty Publications and Presentations

Spinning neutron stars (NSs) can emit continuous gravitational waves (GWs) that carry a wealth of information about the compact object. If such a signal is detected, it will provide us with new insight into the physical properties of matter under extreme conditions. According to binary population synthesis simulations, future space-based GW detectors, such as LISA and TianQin, can potentially detect some double NSs in tight binaries with orbital periods shorter than 10 minutes. The possibility of a successful directed search for continuous GWs from the spinning NS in such a binary system identified by LISA/TianQin will be significantly increased with …

Wallaby Pre-Pilot Survey: Ultra-Diffuse Galaxies In The Eridanus Supergroup, B-Q For, K. Spekkens, L. Stavely-Smith, K. Bekki, A. Karunakaran, B. Catinella, Bärbel S. Koribalski, K. Lee-Waddell, Juan P. Madrid, C. Murugeshan

Physics and Astronomy Faculty Publications and Presentations

We present a pilot study of the atomic neutral hydrogen gas (H I) content of ultra-diffuse galaxy (UDG) candidates. In this paper, we use the pre-pilot Eridanus field data from the Widefield ASKAP L-band Legacy All-sky Blind Survey to search for H I in UDG candidates found in the Systematically Measuring Ultra-diffuse Galaxies survey (SMUDGes). We narrow down to 78 SMUDGes UDG candidates within the maximum radial extents of the Eridanus subgroups for this study. Most SMUDGes UDGs candidates in this study have effective radii smaller than 1.5 kpc and thus fail to meet the defining size threshold. We …

Organizing Pmode Dopplergrams Of Jupiter With Matlab, Brady T. Smith, Deborah Gulledge, Cody Shaw, Gerard Williger

The Cardinal Edge

The interiors of the giant planets are poorly known. At the time of writing, such investigations have been limited to measuring gravitational effects from a handful of orbital probes. The most recent attempt to map the interior is via PMODE (the Planetary Multilevel Oscillations and Dynamics Experiment), designed to explore Jupiter’s core by collecting Dopplergrams. Small radial velocity shifts in Jupiter’s upper cloud decks enable us to map its atmospheric dynamics and consequently its interior via Dioseismology (techniques similar to Helioseismology, applied to Jupiter). This campaign produced a vast dataset with more than 50,000 exposures, every 30 seconds, over 24 …

Find The Distance To The Moon, Dean Smith

AI Assignment Library

This assignment leads students through a series of measurements that lead the student to calculate the distance to the Moon. Students who complete this assignment will see how knowledge that they would normally look up is gathered through experiment and observation.

Axion-Polaritons In The Magnetic Dual Chiral Density Wave Phase Of Dense Qcd, Efrain J. Ferrer, Vivian De La Incera

Physics and Astronomy Faculty Publications and Presentations

We investigate the propagation of electromagnetic radiation in the magnetic dual chiral density wave (MDCDW) phase of dense quark matter. Considering the theory of low-energy fluctuations in this phase, we show how linearly polarized photons reaching the MDCDW medium couple to the fluctuation field to produce two hybridized modes of propagation that we call in analogy with similar phenomenon in condensed matter physics axion polaritons, one of them being gapless and the other gapped. The gapped mode's gap is proportional to the background magnetic field and inversely proportional to the amplitude of the inhomogeneous condensate. The generation of axion …

Rotation Period Distributions And Light Curve Morphologies Of Low Mass Stars And Young Associations, Mark Popinchalk

Dissertations, Theses, and Capstone Projects

This dissertation is centered around the rotation periods of low-mass stars and association of young stars. Rotation periods are a link to the age of the star, as they lose angular momentum over time. To understand how this angular momentum evolves requires understanding the rotation period distributions of a range of stellar types and ages. Traditionally, M dwarf stars and young stars were challenging to describe due to their intrinsic faintness and dispersed sky positions respectively. I approached this subject from several directions.

On The Motion Of The Nodes Of The Moon And The Variation Of Its Inclination To The Ecliptic (An English Translation Of De Motu Nodorum Lunae Eiusque Inclinationis Ad Eclipticam Variatione), Patrick T. Headley

Euleriana

In this paper Euler attempts to explain some features of the motion of the Moon using Newton’s inverse-square law of gravity. He describes the evidence in favor of Newton’s theory but also the lack of progress in the study of lunar motion due to the difficulty of the three-body problem, arising here since both the Sun and the Earth have large effects on the Moon. He proceeds to investigate the line of intersection between the planes of the Earth's orbit and the Moon's orbit, as well as the angle between the two planes.

Using 4most To Refine The Measurement Of Galaxy Properties: A Case Study Of Supernova Hosts, J Dumayne, I M. Hook, S C. Williams, G A. Lowes, D Head, A Fritz, O Graur, Benne Holwerda, A Humphrey, A Milligan, M Nicholl, B F. Roukema, P Wiseman

Faculty Scholarship

The Rubin Observatory’s 10-year Legacy Survey of Space and Time will observe near to 20 billion galaxies. For each galaxy the properties can be inferred. Approximately 105 galaxies observed per year will contain Type Ia supernovae (SNe), allowing SN host-galaxy properties to be calculated on a large scale. Measuring the properties of SN host-galaxies serves two main purposes. The first is that there are known correlations between host-galaxy type and supernova type, which can be used to aid in the classification of SNe. Secondly, Type Ia SNe exhibit correlations between host-galaxy properties and the peak luminosities of the SNe, which …

Tests Of General Relativity Through Searches For Lorentz And Cpt Symmetry Breaking, Kellie Ault

Doctoral Dissertations and Master's Theses

An effective field theory framework, the Standard Model Extension (SME), provides an agnostic, systematic test of General Relativity (GR) and its founding spacetime symmetries, Lorentz and CPT symmetry. Violating these symmetries may provide clues toward unifying the physics of the General Relativity and the Standard Model of particle physics. Part of this work involves the merge of theory, data analysis and experiments with gravitational wave (GW) signals from LIGO/Virgo/KAGRA (LVK) detectors. A modified dispersion relation derived from the SME of GWs is implemented into the LIGO Scientific Collaboration Algorithm Library Suite (LALSuite), where a joint Bayesian inference of the source …

Direct Measurement Of The 114cd(��, ��)115cd Cross Section In The 1 Ev To 300 Kev Energy Range, Kofi Tutu Addo Assumin-Gyimah

Theses and Dissertations

The large thermal cross section of cadmium makes it ideal for many practical applications where screening of thermal neutrons is desired. For example, in non-destructive assay techniques, or for astrophysical studies of the s-process. All such applications require precise knowledge of the neutron-capture cross section on cadmium. Although there are some data on neutron-capture cross sections particularly at thermal energies and at energies relevant for astrophysics, there is very little data at most other energies. Further, the evaluated cross sections from the ENDF and JENDL databases disagree at high energies. Therefore, there is a critical need for precise knowledge of …

Computational And Experimental Study On Undoped And Er-Doped Lithium Tantalate Nanofluorescent Probes, Mkhitar A. Hobosyan, Andrea Pelayo Carvajal, Bhupendra B. Srivastava, Tamanna Zakia, Mohammed Jasim Uddin, Karen S. Martirosyan, Eric Rodriguez, Kofi Nketia Ackaah-Gyasi, Nicholas Dimakis

Physics and Astronomy Faculty Publications and Presentations

We present a combined density functional theory (DFT) and experimental work on lithium tantalate LiTaO3 (LT) and its Er-doped counterparts. We calculate the electronic and optical properties for both LT and LT:Er+3, with Er occupying either Li or Ta sites, at 4.167 mol%. The generalized gradient approximation (GGA) calculations show that the Er-4 f bands appear closer to the conduction band bottom and to the valance band top, for the first and second doped configurations, respectively. This agrees with changes in the imaginary part of the frequency dependent dielectric function between the doped configurations. There are striking differences between the …

Radio Pulsar Searching And Timing Follow-Up, Alexander Eli Mcewen

Theses and Dissertations

Pulsars provide some of the richest laboratories for studying the behavior of ultra-dense matter. As such, they have been utilized for decades to place stringent limits on gravitation and as probes of the material that fills our Galaxy. These tests benefit greatly from a catalog of pulsars that is as complete as possible, which in turn requires thorough searches of the Galaxy and precise timing of discoveries. These searches are informed by the continued characterization of the pulsar population, and so searching techniques develop in tandem with the analysis of their discoveries. Large scale pulsar surveys find pulsars; small scale …

Simulating The Eccentricity Evolution Of Accreting Equal-Mass Binaries: Numerical Sensitivity To The Computational Domain Size And Grid Resolution, Zhongtian Hu

All Theses

With high resolution hydrodynamics simulations, we show that the optimal values of domain radius and grid resolution for the software Sailfish when simulating time-based eccentricity evolution of equal mass, non-circular accreting binaries in a circumbinary disk to be $r_{\rm out} \leq 15a$ and $\delta x / a \le 0.01 $. These values provide a useful guideline for optimizing the performance of simulation runs while maintaining scientific accuracy. Each artificial parameter is probed with 15 runs of 2000 orbits each.