High-Order Finite Difference Methods With Subcell Resolution For Hyperbolic Conservation Laws With Stiff Reaction Terms: Preliminary Results,
2010
Florida International University
High-Order Finite Difference Methods With Subcell Resolution For Hyperbolic Conservation Laws With Stiff Reaction Terms: Preliminary Results, W. Wang, C.-W. Shu, Helen Yee, Bjorn Sjögreen
United States National Aeronautics and Space Administration: Publications
The motivation for this research stems from the high-speed chemical reacting flows which have stiff reaction terms, where the chemical time scales are often much smaller than the fluid dynamics time scales. It is usually too expensive to resolve all the spatial/ temporal scales if we are only interested in the main flow. On the other hand, insufficient spatial/temporal resolution will cause the speed of propagation of discontinuities to be incorrectly predicted for many numerical methods. This numerical phenomenon was first observed by Colella et al. (1986). Then LeVeque & Yee (1990) showed that a similar spurious propagation phenomenon can …
High-Order Simulation Of Hypersonic Nonequilibrium Flows On Overset Grids,
2010
Royal Institute of Technology
High-Order Simulation Of Hypersonic Nonequilibrium Flows On Overset Grids, A. Lani, Bjorn Sjögreen, Helen Yee
United States National Aeronautics and Space Administration: Publications
The time-accurate unsteady 3D compressible flow solver ADPDIS3D is supported by a grant from the Department of Energy (DOE) SciDAC program through the Science Application Partnership (SAP) initiative. The objective of this grant is to develop, implement and validate this variable high-order 3-D multiblock overlapping (overset) grid solver for turbulence with strong shocks and density variations. ADPDIS3D includes capabilities for both direct numerical simulation (DNS), resolving all scales of the flow fields, and large eddy simulation (LES) modeling the small turbulent scales. One of the unique features of the code is the ability to perform DNS and LES computations in …
Effects Of Α-Element Enhancement And The Thermally Pulsing-Asymptotic Giant Branch On Surface Brightness Fluctuation Magnitudes And Broadband Colors,
2010
The University of Texas Rio Grande Valley
Effects Of Α-Element Enhancement And The Thermally Pulsing-Asymptotic Giant Branch On Surface Brightness Fluctuation Magnitudes And Broadband Colors, Hyun Chul Lee, Guy Worthey, John P. Blakeslee
Physics & Astronomy Faculty Publications
We investigate the effects of α-element enhancement and the thermally pulsing-asymptotic giant branch (TP-AGB) stars on the surface brightness fluctuation (SBF) magnitudes and broadband colors of simple stellar populations and compare to the empirical calibrations. We consider a broad range of ages and metallicities using the recently updated Teramo BaSTI isochrones. We find that the α-element-enhanced I-band SBF magnitudes are about 0.35mag brighter and their integrated V - I colors are about 0.02mag redder, mostly because of oxygen-enhancement effects on the upper red giant branch and AGB. We also demonstrate, using both the Teramo BaSTI and Padova isochrones, the acute …
Search For Gravitational-Wave Bursts Associated With Gamma-Ray Bursts Using Data From Ligo Science Run 5 And Virgo Science Run 1,
2010
The University of Texas Rio Grande Valley
Search For Gravitational-Wave Bursts Associated With Gamma-Ray Bursts Using Data From Ligo Science Run 5 And Virgo Science Run 1, B. P. Abbott, R. Abbott, F. Acernese, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano
Physics & Astronomy Faculty Publications
We present the results of a search for gravitational-wave bursts (GWBs) associated with 137 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments during the fifth LIGO science run and first Virgo science run. The data used in this analysis were collected from 2005 November 4 to 2007 October 1, and most of the GRB triggers were from the Swift satellite. The search uses a coherent network analysis method that takes into account the different locations and orientations of the interferometers at the three LIGO-Virgo sites. We find no evidence for GWB signals associated with this sample of GRBs. …
Search For Gravitational Waves From Compact Binary Coalescence In Ligo And Virgo Data From S5 And Vsr1,
2010
The University of Texas Rio Grande Valley
Search For Gravitational Waves From Compact Binary Coalescence In Ligo And Virgo Data From S5 And Vsr1, 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 report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months of data were collected during the Laser Interferometer Gravitational-Wave Observatory’s S5 and Virgo’s VSR1 science runs. The search focused on signals from binary mergers with a total mass between 2 and 35M⊙. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7×10−3 yr−1 L−110, 2.2×10−3 yr−1 L−110, …
All-Sky Search For Gravitational-Wave Bursts In The First Joint Ligo-Geo-Virgo Run,
2010
The University of Texas Rio Grande Valley
All-Sky Search For Gravitational-Wave Bursts In The First Joint Ligo-Geo-Virgo Run, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano, Robert Stone
Physics & Astronomy Faculty Publications
We present results from an all-sky search for unmodeled gravitational-wave bursts in the data collected by the LIGO, GEO 600 and Virgo detectors between November 2006 and October 2007. The search is performed by three different analysis algorithms over the frequency band 50–6000 Hz. Data are analyzed for times with at least two of the four LIGO-Virgo detectors in coincident operation, with a total live time of 266 days. No events produced by the search algorithms survive the selection cuts. We set a frequentist upper limit on the rate of gravitational-wave bursts impinging on our network of detectors. When combined …
The Lisa Gravitational Wave Foreground: A Study Of Double White Dwarfs,
2010
Polish Academy of Sciences
The Lisa Gravitational Wave Foreground: A Study Of Double White Dwarfs, Ashley J. Ruiter, Krzysztof Belczynski, Matthew Benacquista, Shane L. Larson, Gabriel Williams
Physics & Astronomy Faculty Publications
Double white dwarfs (WDs) are expected to be a source of confusion-limited noise for the future gravitational wave observatory LISA. In a specific frequency range, this \"foreground noise\" is predicted to rise above the instrumental noise and hinder the detection of other types of signals, e.g., gravitational waves arising from stellar-mass objects inspiraling into massive black holes. In many previous studies, only detached populations of compact object binaries have been considered in estimating the LISA gravitational wave foreground signal. Here, we investigate the influence of compact object detached and Roche-Lobe overflow (RLOF) Galactic binaries on the shape and strength of …
Buddhist Thought: Murakami Senshō And Critical Buddhism,
2010
Bucknell University
Buddhist Thought: Murakami Senshō And Critical Buddhism, A. Aguilar-Arevalo, Sally Koutsoliotas
Faculty Journal Articles
No abstract provided.
A Spitzer Search For Planetary-Mass Brown Dwarfs With Circumstellar Disks: Candidate Selection,
2010
Bucknell University
A Spitzer Search For Planetary-Mass Brown Dwarfs With Circumstellar Disks: Candidate Selection, Paul M. Harvey, Daniel T. Jaffe, Katelyn N. Allers, Michael Liu
Faculty Journal Articles
No abstract provided.
The Physical And Dynamical Structure Of Serpens - Two Very Different Sub-(Proto)Clusters,
2010
Bucknell University
The Physical And Dynamical Structure Of Serpens - Two Very Different Sub-(Proto)Clusters, A. Duarte-Cabral, G. A. Fuller, N. Peretto, J. Hatchell, Edwin F. Ladd, J. Buckle, J. Richer, S. F. Graves
Faculty Journal Articles
No abstract provided.
Physical Conditions Including Magnetic Fields In Several Star Forming Regions Of The Galaxy,
2010
University of Kentucky
Physical Conditions Including Magnetic Fields In Several Star Forming Regions Of The Galaxy, Matt Lykins
University of Kentucky Doctoral Dissertations
This document describes studies of two independent regions of the interstellar medium (ISM). These studies have the common element that both pertain to regions in our Galaxy that are known to be associated with present-day star formation. These studies aim to help us understand the ISM, star formation, and ultimately where we came from, since, after all, our star, the Sun, is itself the product of star formation 4.5 billion years ago. The first project measured the Zeeman Effect on the 21 cm H I absorption line in order to create a map of the line of sight magnetic fields …
Triplets Of Supermassive Black Holes: Astrophysics Gravitational Waves And Detection,
2010
The University of Texas Rio Grande Valley
Triplets Of Supermassive Black Holes: Astrophysics Gravitational Waves And Detection, Pau Amaro-Seoane, Alberto Sesana, Loren Hoffman, Matthew Benacquista, Christoph Eichhorn, Junichiro Makino, Rainer Spurzem
Physics & Astronomy Faculty Publications
Supermassive black holes (SMBHs) found in the centres of many galaxies are understood to play a fundamental, active role in the cosmological structure formation process. In hierarchical formation scenarios, SMBHs are expected to form binaries following the merger of their host galaxies. If these binaries do not coalesce before the merger with a third galaxy, the formation of a black hole triple system is possible. Numerical simulations of the dynamics of triples within galaxy cores exhibit phases of very high eccentricity (as high as e∼ 0.99). During these phases, intense bursts of gravitational radiation can be emitted at orbital periapsis, …
Searches For Gravitational Waves From Known Pulsars With Science Run 5 Ligo Data,
2010
The University of Texas Rio Grande Valley
Searches For Gravitational Waves From Known Pulsars With Science Run 5 Ligo Data, B. P. Abbott, R. Abbott, F. Acernese, Teviet Creighton, Matthew Benacquista, Mario C. Diaz, Soumya D. Mohanty, Soma Mukherjee, Malik Rakhmanov, Joseph D. Romano
Physics & Astronomy Faculty Publications
We present a search for gravitational waves from 116 known millisecond and young pulsars using data from the fifth science run of the LIGO detectors. For this search, ephemerides overlapping the run period were obtained for all pulsars using radio and X-ray observations. We demonstrate an updated search method that allows for small uncertainties in the pulsar phase parameters to be included in the search. We report no signal detection from any of the targets and therefore interpret our results as upper limits on the gravitational wave signal strength. The most interesting limits are those for young pulsars. We present …
Apparent Faster-Than-Light Pulse Propagation In Interstellar Space: A New Probe Of The Interstellar Medium,
2010
University of Texas Rio Grande Valley
Apparent Faster-Than-Light Pulse Propagation In Interstellar Space: A New Probe Of The Interstellar Medium, F. A. Jenet, D. Fleckenstein, A. Ford, A. Garcia, R. Miller, J. Rivera, K. Stovall
Physics & Astronomy Faculty Publications
Radio pulsars emit regular bursts of radio radiation that propagate through the interstellar medium (ISM), the tenuous gas and plasma between the stars. Previously known dispersive properties of the ISM cause low-frequency pulses to be delayed in time with respect to high frequency ones. This effect can be explained by the presence of free electrons in the medium. The ISM also contains neutral hydrogen that has a well-known resonance at 1420.4 MHz. Electromagnetic theory predicts that at such a resonance, the induced dispersive effects will be drastically different from those of the free electrons. Pulses traveling through a cloud of …
Particle Swarm Optimization And Gravitational Wave Data Analysis: Performance On A Binary Inspiral Testbed,
2010
The University of Texas Rio Grande Valley
Particle Swarm Optimization And Gravitational Wave Data Analysis: Performance On A Binary Inspiral Testbed, Yan Wang, Soumya Mohanty
Physics & Astronomy Faculty Publications
The detection and estimation of gravitational wave signals belonging to a parameterized family of waveforms requires, in general, the numerical maximization of a data-dependent function of the signal parameters. Because of noise in the data, the function to be maximized is often highly multimodal with numerous local maxima. Searching for the global maximum then becomes computationally expensive, which in turn can limit the scientific scope of the search. Stochastic optimization is one possible approach to reducing computational costs in such applications. We report results from a first investigation of the particle swarm optimization method in this context. The method is …
Hard Photodisintegration Of A Proton Pair,
2010
Old Dominion University
Hard Photodisintegration Of A Proton Pair, I. Pomerantz, N. Bubis, K. Allada, A. Beck, B. L. Berman, W. Boeglin, A. Camsonne, M. Canan, K. Chirapatpimol, E. Cisbani
Physics Faculty Publications
We present a study of high energy photodisintegration of proton-pairs through the γ + 3He → p + p + n channel. Photon energies, Eγ , from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. The s−11 scaling of the cross section, as predicted by the constituent counting rule for two nucleon photodisintegration, was observed for the first time. The onset of the scaling is at a higher energy and the cross section is significantly lower than for deuteron (pn pair) photodisintegration. …
Longitudinal Scaling Property Of The Charge Balance Function In Au + Au Collisions At √Snn= 200 Gev,
2010
Old Dominion University
Longitudinal Scaling Property Of The Charge Balance Function In Au + Au Collisions At √Snn= 200 Gev, B. I. Abelev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, B. D. Anderson, D. Arkhipkin, G. S. Averichev, J. Balewski, L. S. Barnby, S. Bültmann, I. Koralt, D. Plyku
Physics Faculty Publications
We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at √sNN = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [ − 1.3 , 1.3 ] . The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width …
Computational Fluctuating Fluid Dynamics,
2010
San Jose State University
Computational Fluctuating Fluid Dynamics, Alejandro Garcia, J. B. Bell, S. Williams
Faculty Publications
This paper describes the extension of a recently developed numerical solver for the Landau-Lifshitz Navier-Stokes (LLNS) equations to binary mixtures in three dimensions. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by using white-noise fluxes. These stochastic PDEs are more complicated in three dimensions due to the tensorial form of the correlations for the stochastic fluxes and in mixtures due to couplings of energy and concentration fluxes (e.g., Soret effect). We present various numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate good agreement with theoretical results and molecular simulation
Search For Gravitational-Wave Inspiral Signals Associated With Short Gamma-Ray Bursts During Ligo's Fifth And Virgo's First Science Run,
2010
California Institute of Technology
Search For Gravitational-Wave Inspiral Signals Associated With Short Gamma-Ray Bursts During Ligo's Fifth And Virgo's First Science Run, J. Abadie, B. P. Abbott, R. Abbott, T. Accadia, F. Acernese, R. Adhikari, P. Ajith, B. Allen, G. Allen, E. Amador Ceron, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, K. G. Arun, Y. Aso, S. Aston, P. Astone, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, D. Barker, F. Barone, B. Barr, P. Barriga, Tiffany Z. Summerscales
Faculty Publications
Progenitor scenarios for short gamma-ray bursts (short GRBs) include coalescenses of two neutron stars or a neutron star and black hole, which would necessarily be accompanied by the emission of strong gravitational waves. We present a search for these known gravitational-wave signatures in temporal and directional coincidence with 22 GRBs that had sufficient gravitational-wave data available in multiple instruments during LIGO's fifth science run, S5, and Virgo's first science run, VSR1. We find no statistically significant gravitational-wave candidates within a [ - 5, + 1)s window around the trigger time of any GRB. Using the Wilcoxon-Mann-Whitney U-test, we find no …
Searches For Gravitational Waves From Known Pulsars With Science Run 5 Ligo Data,
2010
California Institute of Technology
Searches For Gravitational Waves From Known Pulsars With Science Run 5 Ligo Data, B. P. Abbott, R. Abbott, F. Acernese, R. Adhikari, P. Ajith, B. Allen, G. Allen, M. Alshourbagy, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, S. Aoudia, M. A. Arain, M. Araya, H. Armandula, P. Armor, K. G. Arun, Y. Aso, S. Aston, P. Astone, P. Aufmuth, C. Aulbert, S. Babak, P. Baker, G. Ballardin, S. Ballmer, C. Barker, D. Barker, F. Barone, B. Barr, Tiffany Z. Summerscales
Faculty Publications
We present a search for gravitational waves from 116 known millisecond and young pulsars using data from the fifth science run of the LIGO detectors. For this search, ephemerides overlapping the run period were obtained for all pulsars using radio and X-ray observations. We demonstrate an updated search method that allows for small uncertainties in the pulsar phase parameters to be included in the search. We report no signal detection from any of the targets and therefore interpret our results as upper limits on the gravitational wave signal strength. The most interesting limits are those for young pulsars. We present …
