Astrophysics and Astronomy Commons^™

Magnetic Field Effect In The Fine-Structure Constant And Electron Dynamical Mass, Efrain J. Ferrer, A. Sanchez

Physics & Astronomy Faculty Publications

We investigate the effect of an applied constant and uniform magnetic field in the fine-structure constant of massive and massless QED. In massive QED, it is shown that a strong magnetic field removes the so called Landau pole and that the fine-structure constant becomes anisotropic having different values along and transverse to the field direction. Contrary to other results in the literature, we find that the anisotropic fine-structure constant always decreases with the field. We also study the effect of the running of the coupling constant with the magnetic field on the electron mass. We find that in both cases …

Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang

Physics & Astronomy Faculty Publications

We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have analyzed 98 gamma-ray bursts using an unmodeled search method that searches for generic transient gravitational waves and 42 with a modeled search method that targets compact-binary mergers as progenitors of short gamma-ray bursts. Both methods clearly detect the previously reported binary merger signal GW170817, with p-values of z ≤ 1. We estimate 0.07–1.80 joint detections with Fermi-GBM per year for the 2019–20 …

A Rotating Aperture Mask For Small Telescopes, Edward L. Foley

Master's Theses

Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that …

P-13 Astronomy From Ripples In Spacetime, Tiffany Summerscales

Celebration of Research and Creative Scholarship

The LIGO and Virgo detectors have made a total of 11 confirmed measurements of gravitational waves, the faint ripples in the fabric of spacetime predicted by Einstein’s theory of general relativity. Ten of these gravitational wave events were caused by the inspiral, collision, and merging of a pair of black holes and the remaining event by a pair of neutron stars. These measurements have helped us learn about the objects that produced the gravitational waves. Regular candidate detections are now shared in real time with both astronomers and the public.

First Measurement Of Neutrino Oscillation Parameters Using Neutrinos And Antineutrinos By Nova, M. A. Acero, P. Adamson, L. Aliaga, T. Alion, V. Allakhverdian, S. Altakarli, N. Anfimov, A. Antoshkin, A. Aurisano, A. Back, C. Backhouse, M. Baird, N. Balashov, P. Baldi, B. A. Bambah, S. Bashar, K. Bays, S. Bending, R. Bernstein, V. Bhatnagar, Roberto Petti, Et. Al.

Faculty Publications

The NOvA experiment has seen a 4.4σ signal of ⊽ _e appearance in a 2 GeV⊽_μ beam at a distance of 810 km. Using 12.33×10²⁰ protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ⊽_μ→⊽_e candidates with a background of 10.3 and 102⊽_μ→⊽_μ candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm ² ₃₂ | = 2.48 ^+0.11 _-0.06 x 10 ^-3 eV² / c⁴ and sin² θ₂₃ in the ranges …

Estimating The Angular Power Spectrum Of The Gravitational-Wave Background In The Presence Of Shot Noise, Alexander C. Jenkins, Joseph D. Romano, Mairi Sakellariadou

Physics & Astronomy Faculty Publications

There has been much recent interest in studying anisotropies in the astrophysical gravitational-wave (GW) background, as these could provide us with interesting new information about galaxy clustering and large-scale structure. However, this information is obscured by shot noise, caused by the finite number of GW sources that contribute to the background at any given time. We develop a new method for estimating the angular spectrum of anisotropies, based on the principle of combining statistically-independent data segments. We show that this gives an unbiased estimate of the true, astrophysical spectrum, removing the offset due to shot noise power, and that …

Effects Of Solvent Used For Fabrication On Drug Loading And Release Kinetics Of Electrosprayed Temozolomide-Loaded Plga Microparticles For The Treatment Of Glioblastoma, Daniel A. Rodriguez De Anda, Nareg Ohannesian, Karen S. Martirosyan, Sue Anne Chew

Physics & Astronomy Faculty Publications

Glioblastoma multiforme (GBM) is the most common and invasive form of malignant brain tumors and despite advances in surgery, radiotherapy, and chemotherapy, the survival of patients with GBM still remains poor. Temozolomide (TMZ) is the chemotherapy drug that is most commonly given orally after surgical resection of these tumors. In this study, the effects of solvents (i.e., dichloromethane and acetonitrile) used for the fabrication of electrosprayed TMZ-loaded poly(lactic-co-glycolic acid) (PLGA) on drug loading, loading efficiency, drug release kinetics, surface morphology, and particle size were investigated. The results from this study demonstrated that by using a larger volume of a solvent …

Search For Eccentric Binary Black Hole Mergers With Advanced Ligo And Advanced Virgo During Their First And Second Observing Runs, B. P. Abbott, R. Abbott, T. D. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Wenhui Wang

Physics & Astronomy Faculty Publications

When formed through dynamical interactions, stellar-mass binary black holes (BBHs) may retain eccentric orbits (e > 0.1 at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically formed binaries from isolated BBH mergers. Current template-based gravitational-wave searches do not use waveform models associated with eccentric orbits, rendering the search less efficient for eccentric binary systems. Here we present the results of a search for BBH mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. We carried out the search …

Gamma-Ray Bursts Induced By Turbulent Reconnection, A. Lazarian, Bing Zhang, Siyao Xu

Physics & Astronomy Faculty Research

We revisit the Internal-Collision-induced MAgnetic Reconnection and Turbulence model of gamma-ray bursts (GRBs) in view of the advances made in understanding of both relativistic magnetic turbulence and relativistic turbulent magnetic reconnection. We identify the kink instability as the most natural way of changing the magnetic configuration to release the magnetic free energy through magnetic reconnection, as well as driving turbulence that enables fast turbulent reconnection. We show that this double role of the kink instability is important for explaining the prompt emission of GRBs. Our study confirms the critical role that turbulence plays in boosting reconnection efficiency in GRBs and …

The Design And Testing Of A Gamma-Neutron Spectrometer For The Helen Project, Everett Cavanaugh, Christopher Helmerich, Sean Widmier, Sarah Dangelo

Von Braun Symposium Student Posters

No abstract provided.

A Near Horizon Extreme Binary Black Hole Geometry, Jacob Ciafre, Maria J. Rodriguez

All Physics Faculty Presentations

A new solution of four-dimensional vacuum General Relativity is presented. It describes the near horizon region of the extreme (maximally spinning) binary black hole system with two identical extreme Kerr black holes held in equilibrium by a massless strut. This is the first example of a non-supersymmetric, near horizon extreme binary black hole geometry of two uncharged black holes. The black holes are co-rotating, their relative distance is fixed, and the solution is uniquely specified by the mass. Asymptotically, the geometry corresponds to the near horizon extreme Kerr (NHEK) black hole. The binary extreme system has finite entropy.

Binary Black Hole Population Properties Inferred From The First And Second Observing Runs Of Advanced Ligo And Advanced Virgo, B. P. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Satzhan Sitmukhambetov, D. Tuyenbayev, W. H. Wang, Adam Zadrozny

Physics & Astronomy Faculty Publications

We present results on the mass, spin, and redshift distributions with phenomenological population models using the 10 binary black hole (BBH) mergers detected in the first and second observing runs completed by Advanced LIGO and Advanced Virgo. We constrain properties of the BBH mass spectrum using models with a range of parameterizations of the BBH mass and spin distributions. We find that the mass distribution of the more massive BH in such binaries is well approximated by models with no more than 1% of BHs more massive than 45M(circle dot) and a power-law index of alpha = 1.3(-1.7)(+1.4) (90% credibility). …

Wallaby Early Science − V. Askap Hi Imaging Of The Lyon Group Of Galaxies 351, B. Q. For, L. Staveley-Smith, T. Westmeier, M. Whiting, S. -H. Oh, B. Koribalski, J. Wang, O. I. Wong, G. Bekiaris, Juan P. Madrid

Physics & Astronomy Faculty Publications

We present an HI study of the galaxy group LGG 351 usingWidefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY) early science data observed with the Australian Square Kilometre Array Pathfinder (ASKAP). LGG 351 resides behind the M 83 group at a velocity range (cz) of ∼3500–4800 km s−1 within the rich Hydra-Centaurus overdensity region. We detect 40 sources with the discovery of a tidally interacting galaxy pair and two new HI sources that are not presented in previous optical catalogues. 23 out of 40 sources have new redshifts derived from the new HI data. This study is the largest WALLABY …

Search For The Isotropic Stochastic Background Using Data From Advanced Ligo’S Second Observing Run, B. P. Abbott, T. D. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone, Wenhui Wang

Physics & Astronomy Faculty Publications

The stochastic gravitational-wave background is a superposition of sources that are either too weak or too numerous to detect individually. In this study, we present the results from a cross-correlation analysis on data from Advanced LIGO’s second observing run (O2), which we combine with the results of the first observing run (O1). We do not find evidence for a stochastic background, so we place upper limits on the normalized energy density in gravitational waves at the 95% credible level of ΩGW

Directional Limits On Persistent Gravitational Waves Using Data From Advanced Ligo’S First Two Observing Runs, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, Wenhui Wang, Adam Zadrozny, Joseph D. Romano

Physics & Astronomy Faculty Publications

We perform an unmodeled search for persistent, directional gravitational wave (GW) sources using data from the first and second observing runs of Advanced LIGO. We do not find evidence for any GW signals. We place limits on the broadband GW flux emitted at 25 Hz from point sources with a power law spectrum at Fα;Θ < ð0.05–25Þ × 10−8 erg cm−2 s−1 Hz−1 and the (normalized) energy density spectrum in GWs at 25 Hz from extended sources at ΩαðΘÞ < ð0.19–2.89Þ × 10−8 sr−1 where α is the spectral index of the energy density spectrum. These represent improvements of 2.5–3× over previous limits. We also consider point sources emitting GWs at a single frequency, targeting the directions of Sco X-1, SN 1987A, and the Galactic center. The best upper limits on the strain amplitude of a potential source in these three directions range from h0 < ð3.6–4.7Þ × 10−25, 1.5× better than previous limits set with the same analysis method. We also report on a marginally significant outlier at 36.06 Hz. This outlier is not consistent with a persistent gravitational-wave source as its significance diminishes when combining all of the available data

Gwtc-1: A Gravitational-Wave Transient Catalog Of Compact Binary Mergers Observed By Ligo And Virgo During The First And Second Observing Runs, B. P. Abbott, R. Abbott, T. D. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Wenhui Wang

Physics & Astronomy Faculty Publications

We present the results from three gravitational-wave searches for coalescing compact binaries with component masses above 1  𝑀⊙ during the first and second observing runs of the advanced gravitational-wave detector network. During the first observing run (𝑂⁢1), from September 12, 2015 to January 19, 2016, gravitational waves from three binary black hole mergers were detected. The second observing run (𝑂⁢2), which ran from November 30, 2016 to August 25, 2017, saw the first detection of gravitational waves from a binary neutron star inspiral, in addition to the observation of gravitational waves from a total of seven binary black hole mergers, …

Unitarity Of The Infinite-Volume Three-Particle Scattering Amplitude Arising From A Finite-Volume Formalism, Raúl A. Briceño, Maxwell T. Hansen, Stephen R. Sharpe, Adam P. Szczepaniak

Physics Faculty Publications

Hansen and Sharpe [Phys. Rev. D 92, 114509 (2015)] derived a relation between the scattering amplitude of three identical bosons,M₃, and a real function referred to as the divergence-free K matrix and denoted K_df;3. The result arose in the context of a relation between finite-volume energies and K_df;3, derived to all orders in the perturbative expansion of a generic low-energy effective field theory. In this work we set aside the role of the finite volume and focus on the infinite-volume relation between K_df;3 and M₃. We show that, for any …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Wallaby Early Science − V. Askap Hi Imaging Of The Lyon Group Of Galaxies 351, B. Q. For, Lister Staveley-Smith, Tobias Westmeier, M. Whiting, S. -H. Oh, Baerbel Koribalski, Juan P. Madrid

Physics & Astronomy Faculty Publications

We present an HI study of the galaxy group LGG 351 using Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY) early science data observed with the Australian Square Kilometre Array Pathfinder (ASKAP). LGG 351 resides behind the M 83 group at a velocity range (cz) of ∼3500–4800 km s−1 within the rich Hydra-Centaurus overdensity region. We detect 40 sources with the discovery of a tidally interacting galaxy pair and two new HI sources that are not presented in previous optical catalogues. 23 out of 40 sources have new redshifts derived from the new HI data. This study is the largest …

The Gene Silencing Protein Morc-1 Topologically Entraps Dna And Forms Multimeric Assemblies To Cause Dna Compaction., Hyeongjun Kim, Linda Yen, Somsakul P. Wongpalee, Jessica A. Kirshner, Nicita Mehta, Yan Xue, Jonathan B. Johnston, Alma L. Burlingame, John K. Kim, Joseph J. Loparo, Steve E. Jacobsen

Physics & Astronomy Faculty Publications

Highlights

• Caenorhabditis elegans MORC-1 traps DNA loops

• Recruitment of additional MORC-1s cause further loop trapping and DNA compaction

• MORC-1 assemblages become topologically entrapped on DNA

• MORC-1 forms discrete foci in vivo and can phase transition in vitro

Summary

Microrchidia (MORC) ATPases are critical for gene silencing and chromatin compaction in multiple eukaryotic systems, but the mechanisms by which MORC proteins act are poorly understood. Here, we apply a series of biochemical, single-molecule, and cell-based imaging approaches to better understand the function of the Caenorhabditis elegans MORC-1 protein. We find that MORC-1 binds to DNA in a length-dependent but sequence non-specific …

A Precise Determination Of (Anti)Neutrino Fluxes With (Anti)Neutrino-Hydrogen Interactions, H. Duyang, B. Guo, Roberto Petti

Faculty Publications

We present a novel method to accurately determine the flux of neutrinos and antineutrinos, one of the dominant systematic uncertainty affecting current and future long-baseline neutrino experiments, as well as precision neutrino scattering experiment. Using exclusive topologies in v(⊽)-hydrogen interactions, v_µp→µpπ ⁺, ⊽ _µp → µ ⁺pπ, and ⊽_µp → µ ⁺ n with small hadronic energy, we achieve an overall accuracy on the relative fluxes better than 1% in the energy range covering most of the available flux. Since we cannot rely on simulations nor model …

Hyper Wide Field Imaging Of The Local Group Dwarf Irregular Galaxy Ic 1613: An Extended Component Of Metal-Poor Stars, Ragadeepika Pucha, Jeffrey Carlin, Beth Willman, Jay Strader, David Sand, Keith Bechtol, Jean Brodie, Denija Crnojević, Duncan Forbes, Christopher Garling, Jonathan Hargis, Annika Peter, Aaron Romanowsky

Faculty Publications

Stellar halos offer fossil evidence for hierarchical structure formation. Since halo assembly is predicted to be scale-free, stellar halos around low-mass galaxies constrain properties such as star formation in the accreted subhalos and the formation of dwarf galaxies. However, few observational searches for stellar halos in dwarfs exist. Here we present gi photometry of resolved stars in isolated Local Group dwarf irregular galaxy IC 1613 (M sstarf ~ 108 M ⊙). These Subaru/Hyper Suprime-Cam observations are the widest and deepest of IC 1613 to date. We measure surface density profiles of young main-sequence, intermediate to old red giant branch, and …

Fabrication Of Core–Shell Cofe2o4@Hap Nanoparticles: A Novel Magnetic Platform For Biomedical Applications, D. Karthickraja, S. Karthi, G. A. Kumar, Gamage Chamath Dannangoda, Karen S. Martirosyan, E. L. Girija

Physics & Astronomy Faculty Publications

Core–shell CoFe2O4@HAp magnetic nanoparticles were successfully prepared by a simple two-step hydrothermal process, and their physicochemical and magnetic properties were studied. X-ray diffraction and Fourier transform infrared spectroscopy of the as-synthesized samples reveal that the nanoparticles are composed of both phases (HAp@CoFe2O4). The core–shell formation was confirmed by TEM and from the magnetization studies using a vibrating sample magnetometer (VSM), and the ferromagnetic nature of the synthesized core–shell nanoparticles at room temperature was confirmed by saturation magnetization (Ms) and coercivity values of 9.04 emu g−1 and 0.1 T, respectively. It has been observed that heat treatment enhanced the …

Spatially Resolved Stellar Kinematics Of The Ultra-Diffuse Galaxy Dragonfly 44. I. Observations, Kinematics, And Cold Dark Matter Halo Fits, Pieter Van Dokkum, Asher Wasserman, Shany Danieli, Roberto Abraham, Jean Brodie, Charlie Conroy, Duncan Forbes, Christopher Martin, Matt Matuszewski, Aaron Romanowsky, Alexa Villaume

Faculty Publications

We present spatially resolved stellar kinematics of the well-studied ultra-diffuse galaxy (UDG) Dragonfly 44, as determined from 25.3 hr of observations with the Keck Cosmic Web Imager. The luminosity-weighted dispersion within the half-light radius is ${\sigma }_{1/2}={33}_{-3}^{+3}$ km s−1, lower than what we had inferred before from a DEIMOS spectrum in the Hα region. There is no evidence for rotation, with ${V}_{\max }/\langle \sigma \rangle \lt 0.12$ (90% confidence) along the major axis, in possible conflict with models where UDGs are the high-spin tail of the normal dwarf galaxy distribution. The spatially averaged line profile is more peaked than a …

Quantum Algorithms With Applications To Simulating Physical Systems, Anirban Ch Narayan Chowdhury

Physics & Astronomy ETDs

The simulation of quantum physical systems is expected to be an important application for quantum computers. The work presented in this dissertation aims to improve the resource requirements of quantum computers for solving simulation problems, by providing both novel quantum algorithms and improved implementations of existing ones. I present three main results that cover diverse aspects of simulation including equilibrium physics, the preparation of useful quantum states, and simulations based on classical stochastic processes. The results rely on established quantum algorithms and other recent techniques which I review. My first original contribution is a new quantum algorithm to sample from …

Searching For Supermassive Binary Black Holes And Their Gravitational Waves, Karishma Bansal

Physics & Astronomy ETDs

The recent discovery of gravitational waves (GWs) by the LIGO collaboration has opened a new observing window on the universe, but it is limited to the GWs in the frequency range of 10-1000 Hz. The main motivation of this thesis is to consider the possibility of detecting low frequency (nHz) GWs. In the pursuit of these waves, we need to understand their source of origin and build a detector with the required sensitivity. Low-frequency waves are expected as a result of coalescing binary supermassive black holes (SMBBHs). We hope to detect these waves in the near future using pulsar timing …

Studying The Properties Of Sf6 Gas Mixtures For Directional Dark Matter Detection, Randy J. Lafler

Physics & Astronomy ETDs

Although dark matter comprises approximately 85\% of the matter content of the universe, direct detection of dark matter remains elusive. As the available parameter space for dark matter candidates is pushed to lower and lower limits, the demand for larger, more sensitive detectors continues to grow. Although upscaling the detector improves the sensitivity, it greatly increases the cost and complexity of the experiment. Even after a dark matter signal is detected, there remains the possibility that an unknown background mimics the dark matter signal. Consequently, verifying the dark matter origin of a detection signal is an issue for any dark …

Lanczos-Boosted Numerical Linked-Cluster Expansion For Quantum Lattice Models, Krishnakumar Bhattaram, Ehsan Khatami

Faculty Research, Scholarly, and Creative Activity

Numerical linked-cluster expansions allow one to calculate finite-temperature properties of quantum lattice models directly in the thermodynamic limit through exact solutions of small clusters. However, full diagonalization is often the limiting factor for these calculations. Here we show that a partial diagonalization of the largest clusters in the expansion using the Lanczos algorithm can be as useful as full diagonalization for the method while mitigating some of the time and memory issues. As test cases, we consider the frustrated Heisenberg model on the checkerboard lattice and the Fermi-Hubbard model on the square lattice. We find that our approach can surpass …

Circumstellar Sio Masers In The Bulge Asymmetries And Dynamical Evolution Survey, Michael Cullen Stroh

Physics & Astronomy ETDs

The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by using the 43 GHz receivers at the Karl G. Jansky Very Large Array (VLA) and the 86 GHz receivers at the Atacama Large Millimeter/submillimeter Array (ALMA) to observe SiO maser lines in red giant stars. The SiO maser transitions occur at radio frequencies, where extinction is negligible, thus allowing a dense sampling of line-of-sight velocities in the most crowded regions of the Milky Way.

The overall goal of this thesis is to characterize the SiO masers in the …

New Constraints On Early-Type Galaxy Assembly From Spectroscopic Metallicities Of Globular Clusters In M87, Alexa Villaume, Aaron Romanowsky, Jean Brodie, Jay Strader

Faculty Publications

The observed characteristics of globular cluster (GC) systems, such as metallicity distributions, are commonly used to place constraints on galaxy formation models. However, obtaining reliable metallicity values is particularly difficult because of our limited means to obtain high quality spectroscopy of extragalactic GCs. Often, "color–metallicity relations" are invoked to convert easier-to-obtain photometric measurements into metallicities, but there is no consensus on what form these relations should take. In this paper we make use of multiple photometric data sets and iron metallicity values derived from applying full-spectrum stellar population synthesis models to deep Keck/LRIS spectra of 177 GCs centrally located around …