New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. V. The Am Stars Hd 434 And 41 Sextantis,
2010
Tennessee State University
New Precision Orbits Of Bright Double-Lined Spectroscopic Binaries. V. The Am Stars Hd 434 And 41 Sextantis, Francis C. Fekel, Michael H. Williamson
Information Systems and Engineering Management Research Publications
We have detected the secondary component in two previously known spectroscopic binaries, HD 434 and 41 Sex, and for the first time determined double-lined orbits for them. Despite the relatively long period of 34.26 days and a moderate eccentricity of 0.32, combined with the components' rotationally broadened lines, measurement of the primary and secondary radial velocities of HD 434 has enabled us to obtain significantly improved orbital elements. While the 41 Sex system has a much shorter period of 6.167 days and a circular orbit, the estimated V mag difference of 3.2 between its components also makes this a challenging …
Extended Green-Liouville Asymptotics And Vacuum Polarization For Lukewarm Black Holes,
2010
Technological University Dublin
Extended Green-Liouville Asymptotics And Vacuum Polarization For Lukewarm Black Holes, Cormac Breen, Adrian Ottewill
Articles
We consider a quantum field on a lukewarm black hole spacetime. We introduce a new uniform approximation to the radial equation, constructed using an extension of Green-Liouville asymptotics. We then use this new approximation to construct the renormalized vacuum polarization in the Hartle-Hawking vacuum. Previous calculations of the vacuum polarization rely on the WKB approximation to the solutions of the radial equation, however the nonuniformity of the WKB approximations obscures the results of these calculations near both horizons. The use of our new approximation eliminates these obscurities, enabling us to obtain explicitly finite and easily calculable values of the vacuum …
Einstein In The Sky: Black Hole Tales From The Edge Of Space And Time,
2010
Utah State University
Einstein In The Sky: Black Hole Tales From The Edge Of Space And Time, Shane L. Larson
Public Talks
No abstract provided.
Modeling And Simulation On Signatures Of Mars Minerals,
2010
Hampton University
Modeling And Simulation On Signatures Of Mars Minerals, Widad Elmahboub, Edward Yankey, Olivia Kerwin
Virginia Journal of Science
The objective of this study was to assess the feasibility of identifying minerals on Mars using remotely sensed data. In the process we also investigated the effect of noise of Aerosol and dust particles on the spectra of Mars minerals. The remotely sensed data was obtained through modeling and simulation and compared to the lab spectroscopy of the specific minerals in order to make an accurate identification. A linear model was developed using MATLAB Random Number Generator to obtain a simulated image. Part of the information we needed for the linear model was pure pixel information of Mars which was …
Continued Cooling Of The Crust In The Neutron Star Low-Mass X-Ray Binary Ks 1731-260,
2010
University of Michigan
Continued Cooling Of The Crust In The Neutron Star Low-Mass X-Ray Binary Ks 1731-260, Edward M. Cackett, Edward F. Brown, Andrew Cumming, Nathalie Degenaar, Jon M. Miller, Rudy Wijnands
Physics and Astronomy Faculty Research Publications
Some neutron star low-mass X-ray binaries have very long outbursts (lasting several years) which can generate a significant amount of heat in the neutron star crust. After the system has returned to quiescence, the crust then thermally relaxes. This provides a rare opportunity to study the thermal properties of neutron star crusts, putting constraints on the thermal conductivity and hence the structure and composition of the crust. KS 1731-260 is one of only four systems where this crustal cooling has been observed. Here, we present a new Chandra observation of this source approximately eight years after the end of the …
A Multiphase Suzaku Study Of X-Rays From Τ Sco,
2010
Swarthmore College
A Multiphase Suzaku Study Of X-Rays From Τ Sco, R. Ignace, L. M. Oskinova, M. Jardine, J. P. Cassinelli, David H. Cohen, J.-F. Donati, R. H.D. Townsend, A. Ud-Doula
Physics & Astronomy Faculty Works
We obtained relatively high signal-to-noise X-ray spectral data of the early massive star tau Sco (B0.2V) with the Suzaku X-ray Imaging Spectrometer (XIS) instrument. This source displays several unusual features that motivated our study: (1) redshifted absorption in UV P Cygni lines to approximately +250 km s(-1) suggestive of infalling gas, (2) unusually hard X-ray emission requiring hot plasma at temperatures in excess of 10 MK whereas most massive stars show relatively soft X-rays at a few MK, and (3) a complex photospheric magnetic field of open and closed field lines. In an attempt to understand the hard component better, …
A Multi-Phase Suzaku Study Of Τ Sco.,
2010
East Tennessee State University
A Multi-Phase Suzaku Study Of Τ Sco., Richard Ignace, L. Oskinova, M. Jardine, J. Cassinelli, D. Cohen, J.-F. Donati, R. Townsend, A. Ud-Doula
ETSU Faculty Works
We obtained relatively high signal-to-noise X-ray spectral data of the early massive star τ Sco (B0.2V) with the Suzaku X-ray Imaging Spectrometer (XIS) instrument. This source displays several unusual features that motivated our study: (1) redshifted absorption in UV P Cygni lines to approximately +250 km s−1 suggestive of infalling gas, (2) unusually hard X-ray emission requiring hot plasma at temperatures in excess of 10 MK whereas most massive stars show relatively soft X-rays at a few MK, and (3) a complex photospheric magnetic field of open and closed field lines. In an attempt to understand the hard component better, …
New Tests Of General Relativity,
2010
Embry-Riddle Aeronautical University
New Tests Of General Relativity, Quentin Bailey
Publications
The last decade has seen a rapid increase in the number of precision tests of relativity. This research has been motivated by the intriguing possibility that tiny deviations from relativity might arise in the underlying theory that is widely believed to successfully mesh General Relativity (GR) with quantum physics. Many of these tests have been analyzed within an effective field theory framework which generically describes possible deviations from exact relativity and contains some traditional test frameworks as limiting cases. One part of the activity has been a resurgence of interest in tests of relativity in the Minkowski-spacetime context, where Lorentz …
Generalized Acoustic Energy Density And Its Applications,
2010
Brigham Young University - Provo
Generalized Acoustic Energy Density And Its Applications, Buye Xu
Theses and Dissertations
The properties of acoustic kinetic energy density and total energy density of sound fields in lightly damped enclosures have been explored thoroughly in the literature. Their increased spatial uniformity makes them more favorable measurement quantities for various applications than acoustic potential energy density (or squared pressure), which is most often used. In this dissertation, a new acoustic energy quantity, the generalized acoustic energy density (GED), will be introduced. It is defined by introducing weighting factors, α and 1 − α, in the formulation of total acoustic energy density. With the additional degree of freedom, the GED can conform to the …
Cosmic Microwave Background Constraints On Cosmological Models With Large-Scale Isotropy Breaking,
2010
University of Richmond
Cosmic Microwave Background Constraints On Cosmological Models With Large-Scale Isotropy Breaking, Haoxuan Zheng, Emory F. Bunn
Physics Faculty Publications
Several anomalies appear to be present in the large-angle cosmic microwave background anisotropy maps of the Wilkinson Microwave Anisotropy Probe, including the alignment of large-scale multipoles. Models in which isotropy is spontaneously broken (e.g., by a scalar field) have been proposed as explanations for these anomalies, as have models in which a preferred direction is imposed during inflation. We examine models inspired by these, in which isotropy is broken by a multiplicative factor with dipole and/or quadrupole terms. We evaluate the evidence provided by the multipole alignment using a Bayesian framework, finding that the evidence in favor of the model …
The Trilinear Hamiltonian: A Zero-Dimensional Model Of Hawking Radiation From A Quantized Source,
2010
Dartmouth College
The Trilinear Hamiltonian: A Zero-Dimensional Model Of Hawking Radiation From A Quantized Source, Paul D. Nation, Miles P. Blencowe
Dartmouth Scholarship
We investigate a quantum parametric amplifier with dynamical pump mode, viewed as a zero-dimensional model of Hawking radiation from an evaporating black hole. We derive the conditions under which the spectrum of particles generated from vacuum fluctuations deviates from the thermal spectrum predicted for the conventional parametric amplifier. We find that significant deviations arise when the pump mode (black hole) has emitted nearly half of its initial energy into the signal (Hawking radiation) and idler (in-falling particle) modes. As a model of black hole dynamics, this finding lends support to the view that late-time Hawking radiation contains information about the …
Xmm-Newton Observations Of Hd 189733 During Planetary Transits,
2010
Harvard-Smithsonian Center for Astrophysics
Xmm-Newton Observations Of Hd 189733 During Planetary Transits, Ignazio Pillitteri, Scott J. Wolk, Ofer Cohen, Vinay Kashyap, Heather Knutson, Carey M. Lisse, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We report on two XMM-Newton observations of the planetary host star HD 189733. The system has a close in planet and it can potentially affect the coronal structure via interactions with the magnetosphere. We have obtained X-ray spectra and light curves from EPIC and the Reflection Grating Spectrometer on board XMM-Newton which we have analyzed and interpreted. We reduced X-ray data from the primary transit and secondary eclipse that occurred on 2007 April 17 and 2009 May 18, respectively. In the 2007 April observation, only variability due to weak flares is recognized. In 2009 HD 189733 exhibited an X-ray flux …
Optical Discovery Of An Apparent Galactic Supernova Remnant G159.6+7.3,
2010
Dartmouth College
Optical Discovery Of An Apparent Galactic Supernova Remnant G159.6+7.3, Robert A. Fesen, Dan Milisavljevic
Dartmouth Scholarship
Deep Hα images of portions of a faint 3° × 4° Hα shell centered at l = 1596, b = 73 seen on the Virginia Tech Spectral Line Survey images revealed the presence of several thin emission filaments along its eastern limb. Low-dispersion optical spectra of two of these filaments covering the wavelength range of 4500-7500 Å show narrow Hα line emissions with velocities around –170 ± 30 km s–1. Both the morphology and spectra of these filaments are consistent with a Balmer-dominated shock interpretation and we propose that these optical filaments indicate that the large Hα emission …
Discovery Of Cyclic Spot Activity On The G8 Giant Hd 208472,
2010
Ege University
Discovery Of Cyclic Spot Activity On The G8 Giant Hd 208472, Orkun Özdarcan, Serdar Evren, Klaus G. Strassmeier, Thomas Granzer, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We present and analyze 17 consecutive years of UBVRI time-series photometry of the spotted giant component of the RS CVn binary HD 208472. Our aim is to determine the morphology and the evolution of its starspots by using periodsearch techniques and two-spot light-curve modelling. Spots on HD208472 always occur on hemispheres facing the observer during orbital quadrature and flip their location to the opposite hemisphere every approximately six years. The times when the spots change their preferential hemisphere correspond to times when the light curve amplitudes are the smallest and when abrupt changes of the photometric periods are observed. During …
Local Group Dwarf Spheroidals: Correlated Deviations From The Baryonic Tully-Fisher Relation,
2010
Case Western Reserve University
Local Group Dwarf Spheroidals: Correlated Deviations From The Baryonic Tully-Fisher Relation, Stacy S. Mcgaugh
Faculty Scholarship
Local Group dwarf spheroidal satellite galaxies are the faintest extragalactic stellar systems known. We examine recent data for these objects in the plane of the Baryonic Tully-Fisher Relation (BTFR). While some dwarf spheroidals adhere to the BTFR, others deviate substantially. We examine the residuals from the BTFR and find that they are not random. The residuals correlate with luminosity, size, metallicity, ellipticity, and susceptibility of the dwarfs to tidal disruption in the sense that fainter, more elliptical, and tidally more susceptible dwarfs deviate farther from the BTFR. These correlations disfavor stochastic processes and suggest a role for tidal effects. We …
The Climate Of Hd 189733b From Fourteen Transits And Eclipses Measured By Spitzer,
2010
University of California, Santa Barbara
The Climate Of Hd 189733b From Fourteen Transits And Eclipses Measured By Spitzer, Eric Agol, Nicolas B. Cowan, Heather A. Knutson, Drake Deming, Jason H. Steffen, Gregory W. Henry, David Charbonneau
Information Systems and Engineering Management Research Publications
We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope's Infrared Array Camera (IRAC) at 8 μm, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector "ramp" variation with a double-exponential function, which performs better and is a better physical model for this detector variation. Our main scientific findings are (1) an upper limit on the variability of the dayside planet flux of 2.7% (68% confidence); (2) …
A Hot Jupiter Orbiting The 1.7 M☉ Subgiant Hd 102956*,
2010
California Institute of Technology
A Hot Jupiter Orbiting The 1.7 M☉ Subgiant Hd 102956*, John Asher Johnson, Brendan P. Bowler, Andrew W. Howard, Gregory W. Henry, Geoffrey W. Marcy, Howard Isaacson, John Michael Brewer, Debra A. Fischer, Timothy D. Morton, Justin R. Crepp
Information Systems and Engineering Management Research Publications
We report the detection of a giant planet in a 6.4950 day orbit around the 1.68 M☉ subgiant HD 102956. The planet has a semimajor axis a = 0.081 AU and a minimum mass MPsin i =0.96 MJup. HD 102956 is the most massive star known to harbor a hot Jupiter, and its planet is only the third known to orbit within 0.6 AU of a star more massive than 1.5 M☉. Based on our sample of 137 subgiants with M⋆>1.45 M☉, we find that 0.5%–2.3% of A-type stars harbor a close-in planet (a < 0.1 AU) with MPsin i > 1 MJup, consistent with hot-Jupiter …
The California Planet Survey. I. Four New Giant Exoplanets*,
2010
University of California - Berkeley
The California Planet Survey. I. Four New Giant Exoplanets*, Andrew W. Howard, John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Jason T. Wright, David Bernat, Gregory W. Henry, Kathryn M. G. Peek, Howard Isaacson, Kevin Apps, Michael Endl, William D. Cochran, Jeff A. Valenti, Jay Anderson, Nikolai E. Piskunov
Information Systems and Engineering Management Research Publications
We present precise Doppler measurements of four stars obtained during the past decade at Keck Observatory by the California Planet Survey (CPS). These stars, namely, HD 34445, HD 126614, HD 13931, and Gl 179, all show evidence for a single planet in Keplerian motion. We also present Doppler measurements from the Hobby-Eberly Telescope (HET) for two of the stars, HD 34445 and Gl 179, that confirm the Keck detections and significantly refine the orbital parameters. These planets add to the statistical properties of giant planets orbiting near or beyond the ice line, and merit follow-up by astrometry, imaging, and space-borne …
Veritas Search For Vhe Gamma-Ray Emission From Dwarf Spheroidal Galaxies,
2010
Cork Institute of Technology
Veritas Search For Vhe Gamma-Ray Emission From Dwarf Spheroidal Galaxies, P. T. Reynolds, Et. Al.
Physical Sciences Publications
Indirect dark matter searches with ground-based gamma-ray observatories provide an alternative for identifying the particle nature of dark matter that is complementary to that of direct search or accelerator production experiments. We present the results of observations of the dwarf spheroidal galaxies Draco, Ursa Minor, Boötes 1, and Willman 1 conducted by the Very Energetic Radiation Imaging Telescope Array System (VERITAS). These galaxies are nearby dark matter dominated objects located at a typical distance of several tens of kiloparsecs for which there are good measurements of the dark matter density profile from stellar velocity measurements. Since the conventional astrophysical background …
Biofunctionalization And Immobilization Of A Membrane Via Peptide Binding (Cr3-1, S2) By A Monte Carlo Simulation,
2010
University of Southern Mississippi
Biofunctionalization And Immobilization Of A Membrane Via Peptide Binding (Cr3-1, S2) By A Monte Carlo Simulation, Ras B. Pandey, Hendrik Heinz, Jie Feng, Barry L. Farmer
Faculty Publications
A coarse-grained computer simulation model is used to study the immobilization of a dynamic tethered membrane (representation of a clay platelet) in a matrix of mobile peptide chains CR3-1:(1)Trp-(2)Pro-(3)Ser-(4)Ser-(5)Tyr-(6)Leu-(7)Ser-(8)Pro-(9)Ile-(10)Pro-(11)Tyr-(12)Ser and S2:(1)His-(2)Gly-(3)Ile-(4)Asn-(5)Thr-(6)Thr-(7)Lys-(8)Pro-(9)Phe-(10)Lys-(11)Ser-(12)Val on a cubic lattice. Each residue interacts with the membrane nodes with appropriate interaction and executes their stochastic motion with the Metropolis algorithm. Density profiles, binding energy of each residue, mobility, and targeted structural profile are analyzed as a function of peptide concentration. We find that the binding of peptides S2 is anchored by lysine residues ((7)Lys,(10)Lys) while peptides CR3-1 do not bind to membrane. The membrane slows down …
