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Preparing A Database Of Extremely High Velocity Outflows In Quasars, Griffin Kowash, Carla P. Quintero, Sean S. Haas, Paola Rodriguez Hidalgo 2019 Humboldt State University

Preparing A Database Of Extremely High Velocity Outflows In Quasars, Griffin Kowash, Carla P. Quintero, Sean S. Haas, Paola Rodriguez Hidalgo

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Humboldt State University

No abstract provided.


Limits On The Weak Equivalence Principle And Photon Mass With Frb 121102 Subpulses, Nan Xing, He Gao, Jun-Jie Wei, Zhengxiang Li, Weiyang Wang, Bing Zhang, Xue-Feng Wu, Peter Meszaros 2019 Beijing Normal University

Limits On The Weak Equivalence Principle And Photon Mass With Frb 121102 Subpulses, Nan Xing, He Gao, Jun-Jie Wei, Zhengxiang Li, Weiyang Wang, Bing Zhang, Xue-Feng Wu, Peter Meszaros

Physics & Astronomy Faculty Publications

Fast radio bursts (FRBs) are short-duration (~millisecond) radio transients with cosmological origin. The simple sharp features of the FRB signal have been utilized to probe two fundamental laws of physics, namely, testing Einstein's weak equivalence principle and constraining the rest mass of the photon. Recently, Hessels et al. found that after correcting for dispersive delay, some of the bursts in FRB 121102 have complex time–frequency structures that include subpulses with a time–frequency downward drifting property. Using the delay time between subpulses in FRB 121102, here we show that the parameterized post-Newtonian parameter γ is the same for ...


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 2019 Old Dominion University

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 Kdf;3. The result arose in the context of a relation between finite-volume energies and Kdf;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 Kdf;3 and M3. We show that, for any real ...


Wallaby Early Science − V. Askap Hi Imaging Of The Lyon Group Of Galaxies 351, Juan P. Madrid, Bi-Qing For, Lister Staveley-Smith, Tobias Westmeier, M. Whiting, S. -H. Oh, Baerbel Koribalski 2019 The University of Texas Rio Grande Valley

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

Physics and Astronomy Faculty Publications and Presentations

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 ...


Table Of Contents, 2019 University of South Carolina

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.


Space Telescope And Optical Reverberation Mapping Project. Viii. Time Variability Of Emission And Absorption In Ngc 5548 Based On Modeling The Ultraviolet Spectrum, Gerard A. Kriss, Gisella De Rosa, Justin Ely, Bradley M. Peterson, J. Kaastra, M. Mehdipour, Gary J. Ferland, Maryamossadat Dehghanian, S. Mathur, Rick Edelson, Kirk T. Korista, N. Arav, Aaron J. Barth, Misty C. Bentz, W. Niel Brandt, D. Michael Crenshaw, E. Dalla Bonta, K. D. Kenney, C. Done, Michael Eracleous, Michael M. Fausnaugh, E. Gardner, Michael R. Goad, Catherine J. Grier, Keith Horne, Christopher S. Kochanek, I. M. McHardy, Hagai Netzer, Anna Pancoast, L. Pei, Richard W. Pogge, Daniel Proga 2019 Space Telescope Science Institute

Space Telescope And Optical Reverberation Mapping Project. Viii. Time Variability Of Emission And Absorption In Ngc 5548 Based On Modeling The Ultraviolet Spectrum, Gerard A. Kriss, Gisella De Rosa, Justin Ely, Bradley M. Peterson, J. Kaastra, M. Mehdipour, Gary J. Ferland, Maryamossadat Dehghanian, S. Mathur, Rick Edelson, Kirk T. Korista, N. Arav, Aaron J. Barth, Misty C. Bentz, W. Niel Brandt, D. Michael Crenshaw, E. Dalla Bonta, K. D. Kenney, C. Done, Michael Eracleous, Michael M. Fausnaugh, E. Gardner, Michael R. Goad, Catherine J. Grier, Keith Horne, Christopher S. Kochanek, I. M. Mchardy, Hagai Netzer, Anna Pancoast, L. Pei, Richard W. Pogge, Daniel Proga

Physics & Astronomy Faculty Publications

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Lyα and C iv, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data ...


Viewing Angle Constraints On S190425z And S190426c And The Joint Gravitational-Wave/Gamma-Ray Detection Fractions For Binary Neutron Star Mergers, Hao-Ran Song, Shun-Ke Ai, Min-Hao Wang, Nan Xing, He Gao, Bing Zhang 2019 Beijing Normal University

Viewing Angle Constraints On S190425z And S190426c And The Joint Gravitational-Wave/Gamma-Ray Detection Fractions For Binary Neutron Star Mergers, Hao-Ran Song, Shun-Ke Ai, Min-Hao Wang, Nan Xing, He Gao, Bing Zhang

Physics & Astronomy Faculty Publications

The Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo scientific collaboration (LVC) detected two binary neutron star (BNS) merger candidates, S190425z and S190426c. The Fermi-Gamma-ray Burst Monitor (GBM) observed 55.6% (for S190425z) and 100% (for S190426c) of the probability regions of both events at the respective merger times, but no gamma-ray burst (GRB) was detected in either case. The derived luminosity upper limits suggest that a short GRB similar to GRB 170817A would not be detectable for both cases due to their distances, which are larger than that of GW170817. Assuming that the jet profile obtained from GW170817/GRB 170817A ...


Type I Outbursts In Low-Eccentricity Be/X-Ray Binaries, Alessia Franchini, Rebecca G. Martin 2019 University of Nevada, Las Vegas

Type I Outbursts In Low-Eccentricity Be/X-Ray Binaries, Alessia Franchini, Rebecca G. Martin

Physics & Astronomy Faculty Publications

Type I outbursts in Be/X-ray binaries are usually associated with the eccentricity of the binary orbit. The neutron star accretes gas from the outer parts of the decretion disk around the Be star at each periastron passage. However, this mechanism cannot explain type I outbursts that have been observed in nearly circular orbit Be/X-ray binaries. With hydrodynamical simulations and analytic estimates we find that in a circular orbit binary, a nearly coplanar disk around the Be star can become eccentric. The extreme mass ratio of the binary leads to the presence of the 3:1 Lindblad resonance inside ...


The Frequency Of Kozai–Lidov Disc Oscillation Driven Giant Outbursts In Be/X-Ray Binaries, Rebecca G. Martin, Alessia Franchini 2019 University of Nevada, Las Vegas

The Frequency Of Kozai–Lidov Disc Oscillation Driven Giant Outbursts In Be/X-Ray Binaries, Rebecca G. Martin, Alessia Franchini

Physics & Astronomy Faculty Publications

Giant outbursts of Be/X-ray binaries may occur when a Be-star disc undergoes strong eccentricity growth due to the Kozai–Lidov (KL) mechanism. The KL effect acts on a disc that is highly inclined to the binary orbital plane provided that the disc aspect ratio is sufficiently small. The eccentric disc overflows its Roche lobe and material flows from the Be star disc over to the companion neutron star causing X-ray activity. With N-body simulations and steady state decretion disc models we explore system parameters for which a disc in the Be/X-ray binary 4U 0115+634 is KL unstable ...


Correlated Sem, Fib, And Tem Studies Of Material Collected By The Nasa Stardust Spacecraft, Brendan Albert Haas 2019 Washington University in St. Louis

Correlated Sem, Fib, And Tem Studies Of Material Collected By The Nasa Stardust Spacecraft, Brendan Albert Haas

Arts & Sciences Electronic Theses and Dissertations

The objective of this thesis is to describe the study of cometary materials returned by NASA’s Stardust mission. The majority of the research presented in this thesis focuses on improving our characterization and understanding of the fine (< 1 µm) component of comet Wild 2. Investigations of the Stardust foils are conducted with correlated Scanning Electron Microscopy (SEM), Focused Ion Beam (FIB) sample preparation, and Transmission Electron Microscopy (TEM). Investigations of the Stardust aerogels are conducted with plasma ashing sample preparation followed by detailed characterization of the material with TEM. Additional studies of the Stardust interstellar foils, as well as the use of a Convolutional Neural Network (CNN) to search images of the Stardust foils for impact features, are also presented. As a part of this thesis I have developed a new technique for analyzing the Stardust aerogels through the use of plasma ashing sample preparation. This technique is an improvement upon previous attempts to separate cometary materials from the aerogel through the use of HF vapor etching. Plasma ashing allows for cometary materials trapped within the Stardust aerogels to be deposited directly onto TEM grids allowing for detailed characterization of the cometary material with minimal interference from the aerogel itself. The correlated SEM/FIB/TEM studies of the Stardust foils demonstrated here nearly double the number of Stardust craters that have been elementally and structurally characterized in scientific literature. The crater impactor residues were largely composed of combinations of silicates and iron-nickel sulfides that, following impact, rapidly quenched into amorphous melt layers. Two craters were found to contain signatures of the refractory minerals spinel and taenite, indicating a component of the Wild 2 fines originated in the inner Solar System. However, the lack of crystalline material throughout the crater residues suggests that the fine component may largely be composed of amorphous silicates that likely formed in the outer Solar System. Additionally, the submicron Stardust craters appeared enriched in volatile elements relative to CI chondrites, further suggesting that the fine component of Wild 2 originated from a reservoir that was separate from the more refractory coarse (> 1 µm) component. The Stardust aerogel samples returned carbon-rich and potential oldhamite grains. Carbon-rich materials have not been previously observed in the Stardust foils, likely due to the violent collection methods, and the result suggests the ashing technique may be used to better characterize components of the Wild 2 fines that have been difficult to investigate. The presence of oldhamite in the ...


Using Optical And Near-Infrared Photometry To Test Macho Lens Candidates, Ted von Hippel, et al. 2019 University of Texas at Austin

Using Optical And Near-Infrared Photometry To Test Macho Lens Candidates, Ted Von Hippel, Et Al.

Ted von Hippel

We obtained new VLT/ISAAC H-band observations for five MACHO LMC source stars and adjacent LMC field regions. After combining our near-IR photometry with Hubble Space Telescope/PC BVRI optical photometry, we compared the MACHO objects to the adjacent field stars in a variety of color-magnitude and color-color diagrams. These diagnostic diagrams were chosen to be sensitive to our hypothesis that at least some of the MACHO lenses were foreground Galactic disk or thick-disk M dwarfs. For the five lensed objects we studied, our hypothesis could be ruled out for main-sequence lens masses ≥0.1 M☉ for distances out ...


Virgo’S Intracluster Globular Clusters As Seen By The Advanced Camera For Surveys, Benjamin F. Williams, Robin Ciardullo, Ted von Hippel, et al. 2019 Pennsylvania State University

Virgo’S Intracluster Globular Clusters As Seen By The Advanced Camera For Surveys, Benjamin F. Williams, Robin Ciardullo, Ted Von Hippel, Et Al.

Ted von Hippel

We report the discovery of four candidate intracluster globular clusters (IGCs) in a single deepHST ACS field of the Virgo Cluster. We show that each cluster is roughly spherical, has a magnitude near the peak of the Virgo globular cluster luminosity function, has a radial profile that is best fitted by a King model, and is surrounded by an excess of point sources that have the colors and magnitudes of cluster red giant stars. Despite the fact that two of our IGC candidates have integrated colors redder than the mean of the M87 globular cluster system, we propose that ...


Three-Dimensional Spectral Classification Of Low-Metallicity Stars Using Artificial Neural Networks, Shawn Snider, Ted von Hippel, et al. 2019 University of Texas at Austin

Three-Dimensional Spectral Classification Of Low-Metallicity Stars Using Artificial Neural Networks, Shawn Snider, Ted Von Hippel, Et Al.

Ted von Hippel

We explore the application of artificial neural networks (ANNs) for the estimation of atmospheric parameters (Teff, log g, and [Fe/H]) for Galactic F- and G-type stars. The ANNs are fed with medium-resolution (Δλ ~ 1-2 Å) non-flux-calibrated spectroscopic observations. From a sample of 279 stars with previous high-resolution determinations of metallicity and a set of (external) estimates of temperature and surface gravity, our ANNs are able to predict Teff with an accuracy of σ(Teff) = 135-150 K over the range 4250 ≤ Teff ≤ 6500 K, log g with an accuracy of σ(log g) = 0.25-0.30 ...


The White Dwarf Age Of Nfc 2477, Elizabeth J. Jeffery, Ted von Hippel, et al. 2019 Space Telescope Science Institute

The White Dwarf Age Of Nfc 2477, Elizabeth J. Jeffery, Ted Von Hippel, Et Al.

Ted von Hippel

We present deep photometric observations of the open cluster NGC 2477 using HST/WFPC2. By identifying seven cluster white dwarf candidates, we present an analysis of the white dwarf age of this cluster, using both the traditional method of fitting isochrones to the white dwarf cooling sequence, and by employing a new Bayesian statistical technique that has been developed by our group. This new method performs an objective, simultaneous model fit of the cluster and stellar parameters (namely, age, metallicity, distance, reddening, as well as individual stellar masses, mass ratios, and cluster membership) to the photometry. Based on this analysis ...


The White Dwarf Luminosity Function From Sloan Digital Sky Survey Imaging Data, Hugh C. Harris, Jeffrey A. Munn, Mukremin Kilic, James W. Liebert, Kurtis A. Williams, Ted von Hippel, Stephen E. Levine, David G. Monet, Daniel J. Eisenstein, S. J. Kleinman, T. S. Metcalfe, Atsuko Nikka, D. E. Winget, J. Brinkmann, Masataka Fukugita, G. R. Knapp, Robert H. Lupton, J. Allyn Smith, Donald P. Schneider 2019 US Naval Observatory

The White Dwarf Luminosity Function From Sloan Digital Sky Survey Imaging Data, Hugh C. Harris, Jeffrey A. Munn, Mukremin Kilic, James W. Liebert, Kurtis A. Williams, Ted Von Hippel, Stephen E. Levine, David G. Monet, Daniel J. Eisenstein, S. J. Kleinman, T. S. Metcalfe, Atsuko Nikka, D. E. Winget, J. Brinkmann, Masataka Fukugita, G. R. Knapp, Robert H. Lupton, J. Allyn Smith, Donald P. Schneider

Ted von Hippel

A sample of white dwarfs is selected from the Sloan Digital Sky Survey (SDSS) Data Release 3 using their reduced proper motions, based on improved proper motions from combined SDSS and USNO-B data. Numerous SDSS and follow-up spectra (Kilic and coworkers) are used to quantify completeness and contamination of the sample; kinematicsmodels are used to understand and correct for velocity-dependent selection biases.A luminosity function is constructed covering the range 7 < Mbol < 16, and its sensitivity to various assumptions and selection limits is discussed. The white dwarf luminosity function based on 6000 stars is remarkably smooth and rises nearly monotonically to Mbol=15.3. It then drops abruptly, although the small number of low-luminosity stars in the sample and their unknown atmospheric composition prevent quantitative conclusions about ...


Three-Dimensional Spectral Classification Of Low-Metallicity Stars Using Artificial Neural Networks, Shawn Snider, Ted von Hippel, Carlos Allende Prieto, Timothy C. Beers, Christopher Sneden, Et al. 2019 University of Texas

Three-Dimensional Spectral Classification Of Low-Metallicity Stars Using Artificial Neural Networks, Shawn Snider, Ted Von Hippel, Carlos Allende Prieto, Timothy C. Beers, Christopher Sneden, Et Al.

Ted von Hippel

We explore the application of artificial neural networks (ANNs) for the estimation of atmospheric parameters (Teff, log g, and [Fe/H]) for Galactic F- and G-type stars. The ANNs are fed with medium-resolution (Δλ ~ 1-2 Å) non-flux-calibrated spectroscopic observations. From a sample of 279 stars with previous high-resolution determinations of metallicity and a set of (external) estimates of temperature and surface gravity, our ANNs are able to predict Teff with an accuracy of σ(Teff) = 135-150 K over the range 4250 ≤ Teff ≤ 6500 K, log g with an accuracy of σ(log g) = 0.25-0.30 ...


The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted von Hippel, David van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley 2019 Embry-Riddle Aeronautical University

The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley

Ted von Hippel

It takes years of effort employing the best telescopes and in- struments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of life- times of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual ...


The Mystery Deepens: Spitzer Observations Of Cool White Dwarfs, Mukremin Kilic, Ted von Hippel, et al. 2019 University of Texas at Austin

The Mystery Deepens: Spitzer Observations Of Cool White Dwarfs, Mukremin Kilic, Ted Von Hippel, Et Al.

Ted von Hippel

We present 4.5 and 8 µm photometric observations of 18 cool white dwarfs obtained with the Spitzer Space Telescope. Our observations demonstrate that four white dwarfs with Teᶠᶠ < 6000 K show slightly depressed mid-infrared fluxes relative to white dwarf models. In addition, another white dwarf with a peculiar optical and near-infrared spectral energy distribution (LHS 1126) is found to display significant flux deficits in Spitzer observations. These mid-infrared flux deficits are not predicted by the current white dwarf models including collision-induced absorption due to molecular hydrogen. We postulate that either the collision-induced absorption calculations are incomplete or there are other unrecognized physical processes occurring in cool white dwarf atmospheres. The spectral energy distribution of LHS 1126 surprisingly fits a Rayleigh-Jeans spectrum in the infrared, mimicking a hot white dwarf with effective temperature well in excess of 105 K. This implies that the source of this flux deficit is probably not molecular absorption but some other process.


Thirty-Five New Pulsating Da White Dwarf Stars, Anjum S. Mukadam, Ted von Hippel, et al. 2019 University of Texas at Austin

Thirty-Five New Pulsating Da White Dwarf Stars, Anjum S. Mukadam, Ted Von Hippel, Et Al.

Ted von Hippel

We present 35 new pulsating DA (hydrogen atmosphere) white dwarf stars discovered from the Sloan Digital Sky Survey (SDSS) and the Hamburg Quasar Survey (HQS). We have acquired high-speed time series photometry of preselected DA white dwarfs with a prime focus CCD photometer on the 2.1 m telescope at McDonald Observatory over 15 months. We selected these stars on the basis of prior photometric and spectroscopic observations by the SDSS and HQS. For the homogeneous SDSS sample, we achieve a success rate of 80% for finding new variables at a detection threshold of 0.1%-0.3%. With 35 ...


The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted von Hippel, et al. 2019 Youngstown State University

The Resolved Stellar Populations Of A Dwarf Spheroidal Galaxy In The Virgo Cluster, Patrick R. Durell, Ted Von Hippel, Et Al.

Ted von Hippel

We report on the discovery of a faint (MV ~ -10.6 ± 0.2) dwarf spheroidal galaxy on deep F606W and F814W Hubble Space Telescope images of a Virgo intracluster field. The galaxy is easily resolved in our images, as our color magnitude diagram (CMD) extends 1 magnitude beyond the tip of the red giant branch (RGB). Thus, it is the deepest CMD for a small dwarf galaxy inside a cluster environment. Using the colors of the RGB stars, we derive a metal abundance for the dwarf of [M/H] = -2.3 ± 0.3 and show that the metallicity dispersion ...


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