More About Arc-Polarized Structures In The Solar Wind,
2012
Max-Planck-Institut fuer Sonnensystemforschung, Katlenburg-Lindau, Germany
More About Arc-Polarized Structures In The Solar Wind, S A. Haaland, B Sonnerup, G Paschmann
Dartmouth Scholarship
We report results from a Cluster-based study of the properties of 28 arc-polarized magnetic structures (also called rotational discontinuities) in the solar wind. These Alfve ́nic events were selected from the database created and analyzed by Knetter (2005) by use of criteria chosen to elim- inate ambiguous cases. His studies showed that standard, four-spacecraft timing analysis in most cases lacks sufficient accuracy to identify the small normal magnetic field compo- nents expected to accompany such structures, leaving unan- swered the question of their existence. Our study aims to break this impasse. By careful application of minimum vari- ance analysis of …
Search For Gravitational Waves From Intermediate Mass Binary Black Holes,
2012
California Institute of Technology
Search For Gravitational Waves From Intermediate Mass Binary Black Holes, J. Abadie, B. P. Abbott, R. Abbott, T. D. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, C. Affeldt, M. Agathos, K. Agatsuma, P. Ajith, B. Allen, E. Amador Ceron, D. Amariutei, S. B. Anderson, W. G. Anderson, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, P. Astone, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, G. Ballardin, S. Ballmer, Tiffany Z. Summerscales
Faculty Publications
We present the results of a weakly modeled burst search for gravitational waves from mergers of nonspinning intermediate mass black holes in the total mass range 100-450M and with the component mass ratios between 11 and 41. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the intermediate mass black holes mergers as a function of the component masses. In the most efficiently detected bin centered on 88+88M, for nonspinning sources, the rate density …
Search For Gravitational Waves From Intermediate Mass Binary Black Holes,
2012
The University of Texas Rio Grande Valley
Search For Gravitational Waves From Intermediate Mass Binary Black Holes, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano
Physics & Astronomy Faculty Publications
We present the results of a weakly modeled burst search for gravitational waves from mergers of nonspinning intermediate mass black holes in the total mass range 100-450M and with the component mass ratios between 11 and 41. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the intermediate mass black holes mergers as a function of the component masses. In the most efficiently detected bin centered on 88+88M, for nonspinning sources, the rate density …
Polyvinylchloride-Single-Walled Carbon Nanotube Composites: Thermal And Spectroscopic Properties,
2012
The University of Texas Rio Grande Valley
Polyvinylchloride-Single-Walled Carbon Nanotube Composites: Thermal And Spectroscopic Properties, Mircea Chipara, Jessica Cruz, Edgar R. Vega, Jorge Alarcon, Thomas Mion, Dorina M. Chipara, Elamin Ibrahim, Steven C. Tidrow, David Hui
Physics & Astronomy Faculty Publications
Nanocomposites of single-walled carbon nanotubes dispersed within polyvinylchloride have been obtained by using the solution path. High-power sonication was utilized to achieve a good dispersion of carbon nanotubes. Thermogravimetric analysis revealed that during the synthesis, processing, or thermal analysis of these nanocomposites the released chlorine is functionalizing the single-walled carbon nanotubes. The loading of polyvinylchloride by single-walled carbon nanotubes increases the glass transition temperature of the polymeric matrix, demonstrating the interactions between macromolecular chains and filler. Wide Angle X-Ray Scattering data suggested a drop of the crystallite size and of the degree of crystallinity as the concentration of single-walled carbon …
Constraining The Parameters Of Six Known Transiting Exoplanets,
2012
Butler University
Constraining The Parameters Of Six Known Transiting Exoplanets, Mackenzie Lee Jones
Undergraduate Honors Thesis Collection
We present two new transits of GJ~1214b, five of TrES-lb, two of XO~2b, and one each of TrES~3b)WASP-16b and WASP- 36b. These observations were made with multiple observatories including IRTF-MORIS, Butler University's Holcomb Observatory, SARA-KPNO, and SARA-eTIO. Due to poor conditions and a lack of good comparison stars within the field of view, the parameter values for the radius ratio, inclination, and orbital distance, found for GJ-1214b are not reliable. The timing values, while still suspect, suggest consistency with the current ephemeris. After further analysis, the radius ratio we found for TrES-1b in Sloan r' is 0.0.13501±0.0001l, which differs by …
Photoionization Cross Section Measurement Of Rb 5p3/2,
2012
University of Southern Mississippi
Photoionization Cross Section Measurement Of Rb 5p3/2, Charles Young
Honors Theses
The photoionization of atoms is still an emerging field with a foundation in laboratories and journals, yet much in the field is unknown. Photoionization is the phenomenon of an incident photon on a gaseous atom causing the ejection of an electron, and therefore, the atom becomes an ion. The photoelectric effect is a similar but broader term dealing with atoms in all forms: solid, liquid, gas, and plasma. The photoelectric effect causes a current whenever light with a certain wavelength is shined on a metal. The wavelength that is needed to eject an electron is dependent on the atom(s) involved …
Effect Of Compactified Dimensions On The Ground State Energy Of The Hydrogen Atom,
2012
University of Southern Mississippi
Effect Of Compactified Dimensions On The Ground State Energy Of The Hydrogen Atom, Floyd Maseda
Honors Theses
The three-dimensional Hydrogen atom has been explored extensively, and a wavefunction and energy expression can be found in closed form. Little work, however, has been done with higher-dimensional atoms. This discussion focuses on the effects of adding first one then two compactified dimensions to a Hydrogen atom. The metric of the 4-D Hydrogen atom is taken to be R3 × S1 while the 5-D metric is taken to be R3 × S2. We first determine the form of the Laplacian operator in each space and use it to find the respective atomic potentials. The variational method is used to determine …
Chemical Composition Of Comet C/2007 N3 (Lulin): Another ''Atypical'' Comet,
2012
University of Missouri–St. Louis
Chemical Composition Of Comet C/2007 N3 (Lulin): Another ''Atypical'' Comet, Erika Gibb, Boncho Bonev, Geronimo Villanueva, Michael Disanti, Michael Mumma, Emily Sudholt, Yana Radeva
Physics Faculty Works
We measured the volatile chemical composition of comet C/2007 N3 (Lulin) on three dates from 2009 January 30 to February 1 using NIRSPEC, the high-resolution (λ/Δλ ≈ 25,000), long-slit echelle spectrograph at Keck 2. We sampled nine primary (parent) volatile species (H2O, C2H6, CH3OH, H2CO, CH4, HCN, C2H2, NH3, CO) and two product species (OH* and NH2). We also report upper limits for HDO and CH3D. C/2007 N3 (Lulin) displayed an unusual composition when compared to other comets. Based on comets measured to date, CH4 and C2H6 exhibited "normal" abundances relative to water, CO and HCN were only moderately depleted, …
Discovery Of High-Energy And Very High Energy Gamma-Ray Emission From The Blazar Rbs 0413,
2012
Cork Institute of Technology
Discovery Of High-Energy And Very High Energy Gamma-Ray Emission From The Blazar Rbs 0413, P. T. Reynolds, Et. Al.
Physical Sciences Publications
We report on the discovery of high-energy (HE; E > 0.1 GeV) and very high energy (VHE; E > 100 GeV) γ-ray emission from the high-frequency-peaked BL Lac object RBS 0413. VERITAS, a ground-based γ-ray observatory, detected VHE γ rays from RBS 0413 with a statistical significance of 5.5 standard deviations (σ) and a γ-ray flux of (1.5 ± 0.6stat ± 0.7syst) × 10–8 photons m–2 s–1 (~1% of the Crab Nebula flux) above 250 GeV. The observed spectrum can be described by a power law with a photon index of 3.18 ± 0.68stat ± 0.30syst. Contemporaneous observations with the Large Area …
Relativistic Iron K X-Ray Reverberation In Ngc 4151,
2012
University of Maryland
Relativistic Iron K X-Ray Reverberation In Ngc 4151, A. Zoghbi, A. C. Fabian, C. S. Reynolds, E. M. Cackett
Physics and Astronomy Faculty Research Publications
Recent X-ray observations have enabled the study of reverberation delays in active galactic nuclei (AGN) for the first time. All the detections so far are in sources with a strong soft excess, and the measured delay is between the hard (1-3 keV) direct continuum and the soft excess (0.5-1 keV), interpreted as the reflection continuum smeared by relativistic effects. There is however an inherent ambiguity in identifying and studying the details of the lines in the soft excess. Here we report the first detection of reverberation in the iron K band in any AGN. Using XMM-Newton observations of NGC 4151, …
Quantum Quenches In Disordered Systems: Approach To Thermal Equilibrium Without A Typical Relaxation Time,
2012
Georgetown University
Quantum Quenches In Disordered Systems: Approach To Thermal Equilibrium Without A Typical Relaxation Time, Ehsan Khatami, Marcos Rigol, Armando Relaño, Antonio García-García
Faculty Publications
We study spectral properties and the dynamics after a quench of one-dimensional spinless fermions with short-range interactions and long-range random hopping. We show that a sufficiently fast decay of the hopping term promotes localization effects at finite temperature, which prevents thermalization even if the classical motion is chaotic. For slower decays, we find that thermalization does occur. However, within this model, the latter regime falls in an unexpected universality class, namely, observables exhibit a power-law (as opposed to an exponential) approach to their thermal expectation values.
The Ages And Metallicities Of Type Ia Supernova Host Galaxies From The Nearby Galaxies Supernova Search Program,
2012
Western Kentucky University
The Ages And Metallicities Of Type Ia Supernova Host Galaxies From The Nearby Galaxies Supernova Search Program, Suzanna Sadler
Mahurin Honors College Capstone Experience/Thesis Projects
We seek to better understand the physical constraints under which White Dwarf stars ultimately become Type Ia supernovae (SNe Ia), an important test of the robustness of these tools in precisely measuring Dark Energy, as the definite progenitor system still remains elusive. The host galaxy environments of Type Ia supernovae provide our best opportunity for constraining the mechanism(s) of SN Ia production, i.e., the stars involved and the incubation times (tied to stellar ages), and the sensitivity of SNe Ia to changes in the local metallicity. We have measured the ages and metallicities of approximately 60 galaxies from a sample …
The Similarity Of Broad Iron Lines In X-Ray Binaries And Active Galactic Nuclei,
2012
Institute of Astronomy, University of Cambridge
The Similarity Of Broad Iron Lines In X-Ray Binaries And Active Galactic Nuclei, D. J. Walton, R. C. Reis, E. M. Cackett, A. C. Fabian, J. M. Miller
Physics and Astronomy Faculty Research Publications
We have compared the 2001 XMM-Newton spectra of the stellar mass black hole binary XTE J1650-500 and the active galaxy MCG-6-30-15, focusing on the broad, excess emission features at ˜4-7 keV displayed by both sources. Such features are frequently observed in both low-mass X-ray binaries and active galactic nuclei (AGN). For the former case it is generally accepted that the excess arises due to iron emission, but there is some controversy over whether their width is partially enhanced by instrumental processes, and hence also over the intrinsic broadening mechanism. Meanwhile, in the latter case, the origin of this feature is …
Herschel/Spire Observations Of The Dusty Disk Of Ngc 4244.,
2012
University of Louisville
Herschel/Spire Observations Of The Dusty Disk Of Ngc 4244., Benne W. Holwerda, S. Bianchi, T. Boker, D. Radburn-Smith, R. S. De Jong, M. Baes, P. C. Van Der Kruit, M. Xilouris, K. D. Gordon, J. J. Dalcanton
Faculty and Staff Scholarship
We present Herschel/SPIRE images at 250, 350, and 500 μm of NGC 4244, a typical low-mass, disk-only and edge-on spiral galaxy. The dust disk is clumpy and shows signs of truncation at the break radius of the stellar disk. This disk coincides with the densest part of the Hi disk. We compare the spectral energy distribution (SED), including the new SPIRE fluxes, to 3D radiative transfer models; a smooth model disk and a clumpy model with embedded heating. Each model requires a very high value for the dust scale-length (hd = 2−5 h∗), higher dust masses than previous models of …
Optimization Of The Veritas Orbit-Mode Tracking Pattern,
2012
California Polytechnic State University - San Luis Obispo
Optimization Of The Veritas Orbit-Mode Tracking Pattern, Joshua Allen
Physics
Gamma-ray Bursts (GRBs) have not been detected at TeV energies. Detection with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) would open a new window into GRB science. In this paper, we optimize an orbit mode tracking method to search for a GRB at a location provided by the FERMI Gamma-ray satellite. Using Matlab we modeled the orbit tracking pattern. Then we found the optimal offset radii and tracking speed for the telescope to form a uniform image exposure. To optimize the pattern, the model accounts for the maximum 1°/s speed of the telescope’s tracking motors and the camera’s …
Parker Winds Revisited: An Extension To Disk Winds,
2012
University of Nevada, Las Vegas
Parker Winds Revisited: An Extension To Disk Winds, Timothy Waters
UNLV Theses, Dissertations, Professional Papers, and Capstones
A simple 1D dynamical model of thermally driven disk winds is proposed, based on the results of recent, 2.5D axi-symmetric simulations. Our formulation of the disk wind problem is in the spirit of the original Parker (1958) and Bondi (1952) problems, namely we assume an elementary flow configuration consisting of an outflow following pre-defined trajectories in the presence of a central gravitating point mass. Viscosity and heat conduction are neglected. We consider two different streamline geometries, both comprised of straight lines in the (x,z)-plane: (i) streamlines that converge to a geometric point located at (x,z)=(0,-d) and (ii) streamlines that emerge …
X-Ray Emission Line Profiles From Wind Clump Bow Shocks In Massive Stars.,
2012
East Tennessee State University
X-Ray Emission Line Profiles From Wind Clump Bow Shocks In Massive Stars., R. Ignace, W. Waldron, J. Cassinelli, A. Burke
ETSU Faculty Works
The consequences of structured flows continue to be a pressing topic in relating spectral data to physical processes occurring in massive star winds. In a preceding paper, our group reported on hydrodynamic simulations of hypersonic flow past a rigid spherical clump to explore the structure of bow shocks that can form around wind clumps. Here we report on profiles of emission lines that arise from such bow shock morphologies. To compute emission line profiles, we adopt a two-component flow structure of wind and clumps using two “beta” velocity laws. While individual bow shocks tend to generate double-horned emission line profiles, …
Late-Time Optical Emission From Core-Collapse Supernovae,
2012
Dartmouth College
Late-Time Optical Emission From Core-Collapse Supernovae, Dan Milisavljevic, Robert A. Fesen, Roger A. Chevalier, Robert P. Kirshner
Dartmouth Scholarship
Ground-based optical spectra and Hubble Space Telescope images of 10 core-collapse supernovae (CCSNe) obtained several years to decades after outburst are analyzed with the aim of understanding the general properties of their late-time emissions. New observations of SN 1957D, 1970G, 1980K, and 1993J are included as part of the study. Blueshifted line emissions in oxygen and/or hydrogen with conspicuous line substructure are a common and long-lasting phenomenon in the late-time spectra. Followed through multiple epochs, changes in the relative strengths and velocity widths of the emission lines are consistent with expectations for emissions produced by interaction between SN ejecta and …
Synthesis And Upconversion Spectroscopy Of Yb Er Doped M2o2s (M = La, Gd, Y) Phosphors,
2012
University of Texas at San Antonio
Synthesis And Upconversion Spectroscopy Of Yb Er Doped M2o2s (M = La, Gd, Y) Phosphors, G. A. Kumar, Madhab Pokhrel, Dhiraj K. Sardar, Alejandrina Martinez
Physics & Astronomy Faculty Publications
Yb and Er doped M2O2S (M = Y, Gd, La) phosphor was synthesized by solid state flux fusion method and their up conversion spectral properties were studied as a function different Yb concentrations. The solid state flux fusion results in well crystallized hexagonal shaped phosphor particles of average size 4–6 μm. Upconversion spectral studies shows that all the compositions are stronger in green emission with the green emission intensity 1.7 times than the red in composition Gd2O2S:Yb(8)Er(1), Y2O2S:Yb(9)Er(1), La2O2S:Yb(3)Er(7) (All mol%). The internal upconversion efficiency for the green emission bands was calculated to be 74, 62, 100% respectively in …
Book Review: Astronomy At The Frontiers Of Science,
2012
Florida Institute of Technology
Book Review: Astronomy At The Frontiers Of Science, T. D. Oswalt
Publications
This document is Dr. Oswalt’s review of Astronomy at the Frontiers of Science, edited by Jean-Pierre Lasota, Springer, 2011. 357p, 9789400716575 $179.00.
