Astrophysics and Astronomy Commons^™

Data From: How Uncertainty In The Neutral Wind Limits The Accuracy Of Ionospheric Modeling And Forecasting, Michael David, Jan Sojka, Robert W. Schunk

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Output files from runs of the TDIM ionospheric model used for the figures and calculations in the article in JGR Space Physics.

Construction Of An Optical Fiber Strian Gauge, Najwa Sulaiman

Master's Theses and Doctoral Dissertations

This project is focused on the construction of an optical fiber strain gauge that is based on a strain gauge described by Butter and Hocker. Our gauge is designed to generate an interference pattern from the signals carried on two bare single-mode fibers that are fastened to an aluminum cantilever. When the cantilever experiences flexural stress, the interference pattern should change. By observing this change, it is possible to determine the strain experienced by the cantilever. I describe the design and construction of our optical fiber strain gauge as well as the characterization of different parts of the apparatus.

Investigation Of Lunar Subsurface Cavities Using Thermal Inertia And Temperature Maximum To Minimum Ratios, Rachel Ann Slank

Open Access Theses & Dissertations

Previous studies have revealed a small number of subsurface cavities, including lava tubes, as well as skylights, lava flow pits, and impact melt pits on the Moon. The interiors of subsurface cavities would have been protected from micrometeorite bombardment, solar radiation, space weathering, and extreme diurnal temperature swings over long periods of geologic time. As a result, subsurface cavities can provide access to pristine crustal samples and stratigraphy. These cavities may also harbor important volatiles, such as water ice, that would enable future exploration missions by relieving many operational constraints, including the supply of propellants and life support. In addition, …

Equation Of State Of A Dense And Magnetized Neutron System, Md Masud

Open Access Theses & Dissertations

Neutron stars (NSs) are the windows to check the validation of physical laws at extreme conditions, for example, at very high densities and strong magnetic fields and thus to reach the equations of state (EoS) for a better understanding of the structure as well as the composition of the NSs. In our investigations, it is found that the system's (NSs) pressure becomes anisotropic due to the breaking of rotational symmetry in the presence of strong magnetic fields, which even can be significantly sufficient to lead into the deformation of NSs or to destroy itself.

Rapid Orbit Refinement Of Potential Near-Earth Objects And Recovery Of Nearly Lost Asteroids, Austin Lantz Caughey

Theses and Dissertations

The Minor Planet Center alerts researchers about potential discoveries of new Near-Earth Objects (NEOs) on their NEO Confirmation Page (NEOCP). Most of these are indeed previously unstudied objects, which must be studied very promptly while initial predictions of their motions are still accurate. My thesis project has focused on the observation of these bodies, and the submission of their measured positions to the MPC within a few hours of observation. Data has been obtained using the Skynet Robotic Telescope Network, including the R-COP telescope in Perth, Australia; the PROMPT 3 telescope in La Serena, Chile; and Yerkes Observatory in Williams …

First Measurement Of The Helicity Asymmetry E In Ƞ Photoproduction On The Proton, I. Senderovich, B.T. Morrison, M. Dugger, B.G. Ritchie, E. Pasyuk, R. Tucker, J. Brock, C. Carlin, C.D. Keith, D. G. Meekins, Y. Prok

Physics Faculty Publications

Results are presented for the first measurement of the double-polarization helicity asymmetry E for the ƞ photoproduction reaction ɣp -> ηp. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the Jülich-Bonn model to examine the case for the existence of a narrow N* resonance between 1.66 and 1.70 GeV. The addition of these data to the …

Measurements Of Dⁿ² And Aⁿ¹: Probing The Neutron Spin Structure, D. Flay, M. Posik, D. S. Parno, K. Allada, M. Canan, C. Hyde, Jefferson Lab Hall A Collaboration

Physics Faculty Publications

We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element d₂ of the neutron dⁿ₂ was conducted. The quantity dⁿ₂ represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the ³He spin structure functions, g₁ and g₂, after nuclear corrections had been applied to these …

Bright Galaxies At Hubble's Redshift Detection Frontier : Preliminary Results And Design From The Redshift Z ~ 9-10 Borg Pure-Parallel Hst Survey., V. Calvi, M. Trenti, M. Stiavelli, P. A. Oesch, L. Bradley, K. B. Schmidt, D. Coe, G. Brammer, S. Bernard, R. J. Bouwens, D. Carrasco, C. M. Carollo, Benne W. Holwerda, J. W. Mackenty, C. A. Mason, J. M. Shull, T. Treu

Faculty and Staff Scholarship

We present the first results and design from the redshift z ∼ 9–10 Brightest of the Reionizing Galaxies Hubble Space Telescope survey BoRG[z9–10], aimed at searching for intrinsically luminous unlensed galaxies during the first 700 Myr after the Big Bang. BoRG[z9–10] is the continuation of a multi-year pure-parallel near-IR and optical imaging campaign with the Wide Field Camera 3. The ongoing survey uses five filters, optimized for detecting the most distant objects and offering continuous wavelength coverage from λ = 0.35 μm to λ = 1.7 μm. We analyze the initial ∼130 arcmin2 of area over 28 independent lines of …

Dynamical Formation Of Protoplanetesimals, Akbar Whizin

Electronic Theses and Dissertations

The seeds of planetesimals that formed in the gaseous protoplanetary disk (PPD) have many barriers to overcome in their growth from millimeter to meter-sized and larger bodies. Centimeter-sized aggregates are weakly bound and self-gravity is almost non-existent so surface forces play a critical role in holding small loosely-bound rubble-piles together. Their orbital motions and effects form disk processes impart relative velocities leading to collisions so understanding the macroscopic disk environment is also necessary. To this end we analyze the dynamics of particles in Saturn's F ring as an analogue to understanding the orbital evolution of proto-planetesimals embedded in a PPD. …

Molecular Regulation Of Trophoblast Survival During Placentation And Pathologies Of Placental Insufficiency, Chandni V. Jain

Wayne State University Dissertations

HBEGF, is present in the uterus at the time of embryo implantation and protects first

trimester TB cells from apoptosis and promotes their invasion. The hypertensive disease, PE, in

which TB invasion of the uterine arteries is reduced and TB apoptosis is elevated, is

characterized by a reduction in HBEGF expression. In this study using a first trimester cell line

and villous explant culture key components involved in HBEGF survival signaling pathway were

identified. Specific MMP inhibitors established the requirement for MMP2 in HBEGF shedding

and upregulation. NGS identified a HIF regulated gene, HSPA6 (HSP70B’) and using specific

inhibitors it …

Improved Analysis Of Gw150914 Using A Fully Spin-Precessing Waveform Model, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-one body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessingspin waveform model (precessing EOBNR) developed within the EOB formalism. We find good agreement with the …

Binary Black Hole Mergers In The First Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, F. Acernese, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers. In this paper, we present full results from a search for binary black hole merger signals with total masses up to 100M· and detailed implications from our observations of these systems. Our search, based on general-relativistic models of gravitational-wave signals from binary black hole systems, unambiguously identified two signals, GW150914 and GW151226, with a significance of greater than 5s over the observing period. It also identified a third possible signal, LVT151012, …

Extragalactic Archeology With The Ghosts Survey : I. Age-Resolved Disk Structure Of Nearby Low-Mass Galaxies., David Streich, Roelof S. De Jong, Jeremy Bailin, Eric F. Bell, Benne W. Holwerda, Ivan Minchev, Antonela Monachesi, David J. Radburn-Smith

Faculty and Staff Scholarship

Aims. We study the individual evolution histories of three nearby low-mass edge-on galaxies (IC 5052, NGC 4244, and NGC 5023).

Methods. Using resolved stellar populations, we constructed star count density maps for populations of different ages and analyzed the change of structural parameters with stellar age within each galaxy.

Results. We do not detect a separate thick disk in any of the three galaxies, even though our observations cover a wider range in equivalent surface brightness than any integrated light study. While scale heights increase with age, each population can be well described by a single disk. Two of the …

Spectroscopic And Spectro-Astrometric Analysis Of T Tauri Stars, Logan Ryan Brown

Doctoral Dissertations

"To understand our own solar origins, we must investigate the composition of the protoplanetary disk from which the solar system formed. To infer this, we study analogs to the early solar system called T Tauri stars. These objects are low-mass, pre-main sequence stars surrounded by circumstellar disks of material from which planets are believed to form. We present high-resolution, near-infrared spectroscopic data for the T Tauri stars DR Tau and AA Tau using NIRSPEC at the Keck II telescope. For DR Tau, a spectro-astrometric analysis was performed, obtaining sub-seeing spatial information on water emission. Alongside a disk model, we constrained …

First Results From The Madcash Survey: A Faint Dwarf Galaxy Companion To The Low-Mass Spiral Galaxy Ngc 2403 At 3.2 Mpc*, Jeffrey Carlin, David Sand, Paul Price, Beth Willman, Ananthan Karunakaran, Kristine Spekkens, Eric Bell, Jean Brodie, Denija Crnojević, Duncan Forbes, Jonathan Hargis, Evan Kirby, Robert Lupton, Annika Peter, Aaron Romanowsky, Jay Strader

Faculty Publications

No abstract provided.

A High Stellar Velocity Dispersion And ~100 Globular Clusters For The Ultra-Diffuse Galaxy Dragonfly 44, Pieter Van Dokkum, Roberto Abraham, Jean Brodie, Charlie Conroy, Shany Danieli, Allison Merritt, Lamiya Mowla, Aaron Romanowsky, Jielai Zhang

Faculty Publications

No abstract provided.

Probing Physical Conditions In The Crab Nebula With Emission Line Analysis, Xiang Wang

Theses and Dissertations--Physics and Astronomy

We present a range of steady-state photoionization simulations, corresponding to different assumed shell geometries and compositions, of the unseen postulated rapidly expanding outer shell to the Crab Nebula. The properties of the shell are constrained by the mass that must lie within it, and by limits to the intensities of hydrogen recombination lines. In all cases the photoionization models predict very strong emission from high ionization lines that will not be emitted by the Crab’s filaments, alleviating problems with detecting these lines in the presence of light scattered from brighter parts of the Crab. The NIR [Ne VI] λ 7.652 …

Effect Of Polymer Concentration, Rotational Speed, And Solvent Mixture On Fiber Formation Using Forcespinning, Nancy Obregon, Victor Agubra, Madhab Pokhrel, Howard Campos, David Flores, David De La Garza, Yuanbing Mao, Javier Macossay, Mataz Alcoutlabi

Physics & Astronomy Faculty Publications

Polycaprolactone (PCL) fibers were produced using Forcespinning® (FS). The effects of PCL concentration, solvent mixture, and the spinneret rotational speed on fiber formation were evaluated. The concentration of the polymer in the solvents was a critical determinant of the solution viscosity. Lower PCL concentrations resulted in low solution viscosities with a correspondingly low fiber production rate with many beads. Bead-free fibers with high production rate and uniform fiber diameter distribution were obtained from the optimum PCL concentration (i.e., 12.5 wt%) with tetrahydrofuran (THF) as the solvent. The addition of N, N-dimethylformamide (DMF) to the THF solvent promoted the gradual formation …

The Surface Density Profile Of The Galactic Disk From The Terminal Velocity Curve, Stacy S. Mcgaugh

Faculty Scholarship

The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For R0 = 8 kpc, the models have stellar mass 5 < M∗ < 6 × 1010 , scale length 2.0 ≤ Rd ≤ 2.9 kpc, LSR circular velocity 222 ≤ Θ0 ≤ 233 , and solar circle stellar surface density 34 ≤ Σd(R0) ≤ 61 . The present interarm location of the solar neighborhood may have a somewhat lower stellar surface density than average for the solar circle. The Milky Way appears to be a normal spiral galaxy that obeys scaling relations like the Tully-Fisher relation, the size-mass relation, and the disk maximality-surface brightness relation. The stellar disk is maximal, and the spiral arms are massive. The bumps and wiggles in the terminal velocity curve correspond to known spiral features (e.g., the Centaurus arm is a ∼50% overdensity). The rotation curve switches between positive and negative over scales of hundreds of parsecs. The rms amplitude , implying that commonly neglected terms in the Jeans equations may be nonnegligible. The spherically averaged local dark matter density is ρ0,DM ≈ 0.009 (0.34 ). Adiabatic compression of the dark matter halo may help reconcile the Milky Way with the c-V200 relation expected in ΛCDM while also helping to mitigate the too-big-to-fail problem, but it remains difficult to reconcile the inner bulge/bar-dominated region with a cuspy halo. We note that NGC 3521 is a near twin to the Milky Way, having a similar luminosity, scale length, and rotation curve.

Mapping Gravitational-Wave Backgrounds Of Arbitrary Polarisation Using Pulsar Timing Arrays, Jonathan Gair, Joseph D. Romano, Stephen R. Taylor

Physics & Astronomy Faculty Publications

We extend our previous work on mapping gravitational-wave backgrounds using techniques borrowed from the analysis of cosmic microwave background data to backgrounds which have non-general-relativity (non-GR) polarisations. Our analysis and results are presented in the context of pulsar timing array observations, but the overarching methods are general, and can be easily applied to LIGO or eLISA observations using appropriately modified response functions. Analytic expressions for the pulsar timing response to gravitational waves with non-GR polarisation are given for each mode of a spin-weighted spherical-harmonic decomposition of the background, which permit the signal to be mapped across the sky to any …

Pre-Mission Input Requirements To Enable Successful Sample Collection By A Remote Field/Eva Team, Barbara A. Cohen, Darlene S. S. Lim, Kelsey E. Young, Anna Brunner, Richard C. Elphic, Audrey Horne, Mary C. Kerrigan, Gordon O. Osinski, John R. Skok, Steven W. Squyres, David Saint-Jacques, Jennifer L. Heldmann

Journal of Human Performance in Extreme Environments

We used a field excursion to the West Clearwater Lake Impact structure as an opportunity to test factors that contribute to the decisions a remote field team (for example, astronauts conducting extravehicular activities (EVA) on planetary surfaces) makes while collecting samples for return to Earth. We found that detailed background on the analytical purpose of the samples, provided to the field team, enables them to identify and collect samples that meet specific analytical objectives. However, such samples are not always identifiable during field reconnaissance activities, and may only be recognized after outcrop characterization and interpretation by crew and/or science team …

A Search For Correlations Between Gamma-Ray Burst Variability And Afterglow Onset, Sarah A. Yost

Physics Faculty Publications

We compared the time (or time limit) of onset for optical afterglow emission to the γ-ray variability V in 76 gamma-ray bursts with redshifts. In the subset (25 cases) with the rise evident in the data, we fit the shape of the onset peak as well and compared the rising and decaying indices to V. We did not find any evidence for any patterns between these properties and there is no statistical support for any correlations. This indicates a lack of connection between irregularities of the prompt γ-ray emission and the establishment of the afterglow phase. In the ordinary …

Sdss-Iv/Manga: Spectrophotometric Calibration Technique, Renbin Yan, Christy Tremonti, Matthew A. Bershady, David R. Law, David J. Schlegel, Kevin Bundy, Niv Drory, Nicholas Macdonald, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Brian Cherinka, Arthur Eigenbrot, James E. Gunn, Paul Harding, David W. Hogg, José R. Sánchez-Gallego, Sebastian F. Sánchez, David A. Wake, Anne-Marie Weijmans, Ting Xiao, Kai Zhang

Physics and Astronomy Faculty Publications

Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV, is an integral-field spectroscopic survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2'' fibers to obtain resolved spectroscopy over a wide wavelength range of 3600–10300 Å. To map the internal variations within each galaxy, we need to perform accurate spectral surface photometry, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due …

A Deep Look At The Nuclear Region Of Ugc 5101 Through High Angular Resolution Mid-Ir Data With Gtc/Canaricam, M. Martínez-Paredes, Almudena Alonso-Herrero, Itziar Aretxaga, C. Ramos Almeida, A. Hernán-Caballero, O. González-Martín, M. Pereira-Santaella, Christopher Packham, A. Asensio Ramos, T. Díaz-Santos, Moshe Elitzur, P. Esquej, I. García-Bernete, Masatoshi Imanishi, Nancy A. Levenson, José Miguel Rodríguez Espinosa

Physics and Astronomy Faculty Publications

We present an analysis of the nuclear infrared (IR, 1.6–18 μm) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR high angular resolution (0.3–0.5 arcsec) imaging using the Si-2 filter (λ_C = 8.7 μm) and 7.5–13 μm spectroscopy taken with CanariCam (CC) on the 10.4 m Gran Telescopio CANARIAS. We also use archival Hubble Space Telescope/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate the near- and mid-IR unresolved nuclear emission by modelling the imaging data with GALFIT. We decompose …

Strong Variability Of The Coronal Line Region In Ngc 5548, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present the second extensive study of the coronal line variability in an active galaxy. Our data set for the well-studied Seyfert galaxy NGC 5548 consists of five epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about five years and three epochs of X-ray spectroscopy overlapping in time with it. Whereas the broad emission lines and hot dust emission varied only moderately, the coronal lines varied strongly. However, the observed high variability is mainly due to a flux decrease. Using the optical [Fe vii] and X-ray O vii emission lines we estimate that the coronal line gas …

Coherent Network Analysis For Continuous Gravitational Wave Signals In A Pulsar Timing Array: Pulsar Phases As Extrinsic Parameters, Yan Wang, Soumya D. Mohanty, F. A. Jenet

Physics & Astronomy Faculty Publications

Supermassive black hole binaries are one of the primary targets of gravitational wave (GW) searches using pulsar timing arrays (PTAs). GW signals from such systems are well represented by parameterized models, allowing the standard Generalized Likelihood Ratio Test (GLRT) to be used for their detection and estimation. However, there is a dichotomy in how the GLRT can be implemented for PTAs: there are two possible ways in which one can split the set of signal parameters for semi-analytical and numerical extremization. The straightforward extension of the method used for continuous signals in ground-based GW searches, where the so-called pulsar phase …

Di-Hadron Correlations With Identified Leading Hadrons In 200 Gev Au + Au And D + Au Collisions At Star, James K. Adkins, Renee H. Fatemi, Suvarna Ramachandran, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, X. Bai

Physics and Astronomy Faculty Publications

The STAR Collaborationpresents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au+Au and minimum-bias d+Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. …

On Calculating The Current-Voltage Characteristic Of Multi-Diode Models For Organic Solar Cells, Ken Roberts, Sree Ram Valluri

Physics and Astronomy Publications

We provide an alternative formulation of the exact calculation of the current-voltage characteristic of solar cells which have been modeled with a lumped parameters equivalent circuit with one or two diodes. Such models, for instance, are suitable for describing organic solar cells whose current-voltage characteristic curve has an inflection point, also known as an S-shaped anomaly. Our formulation avoids the risk of numerical overflow in the calculation. It is suitable for implementation in Fortran, C or on micro-controllers.

The Young Solar Analogs Project. I. Spectroscopic And Photometric Methods And Multi-Year Timescale Spectroscopic Results, R. O. Gray, Jon M. Saken, C. J. Corbally, M. M. Briley, R. A. Lambert, I. M. Newsome, M. F. Seeds, Y. Kahvaz

Physics Faculty Research

This is the first in a series of papers presenting methods and results from the Young Solar Analogs Project, which began in 2007. This project monitors both spectroscopically and photometrically a set of 31 young (300–1500 Myr) solar-type stars with the goal of gaining insight into the space environment of the Earth during the period when life first appeared. From our spectroscopic observations we derive the Mount Wilson S chromospheric activity index (SMW), and describe the method we use to transform our instrumental indices to SMW without the need for a color term. We introduce three photospheric …

Gamma-Rays From The Quasar Pks 1441+25: Story Of An Escape, P. T. Reynolds, Et Al

Physical Sciences Publications

Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the universe. The detection of significant emission above 100 GeV from a distant quasar would show that some of the radiated gamma-rays escape pair-production interactions with low-energy photons, be it the extragalactic background light (EBL), or the radiation near the supermassive black hole lying at the jet's base. VERITAS detected gamma-ray emission up to ~200 GeV from PKS 1441+25 (z = 0.939) during 2015 April, a period of high activity across all wavelengths. This observation of …