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2008

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Articles 181 - 210 of 229

Full-Text Articles in Astrophysics and Astronomy

Poet: Polarimeters For Energetic Transients, J E. Hill, Mark L. Mcconnell, Peter F. Bloser, Jason S. Legere, John R. Macri, James M. Ryan, Scott Barthelmy, L Angelini, Takanori Sakamoto, J Kevin Black, H Hartmann, Philip Kaaret, Bing Zhang, Kunihito Ioka, Takashi Nakamura, Kenji Toma, Ryo Yamazaki, X Wu Jan 2008

Poet: Polarimeters For Energetic Transients, J E. Hill, Mark L. Mcconnell, Peter F. Bloser, Jason S. Legere, John R. Macri, James M. Ryan, Scott Barthelmy, L Angelini, Takanori Sakamoto, J Kevin Black, H Hartmann, Philip Kaaret, Bing Zhang, Kunihito Ioka, Takashi Nakamura, Kenji Toma, Ryo Yamazaki, X Wu

Space Science Center

POET (Polarimeters for Energetic Transients) is a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2–15 keV and a high energy polarimeter (Gamma‐Ray Polarimeter Experiment—GRAPE) that will measure polarization in the 60–500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The POET spacecraft provides a zenith‐pointed platform for maximizing the exposure to deep space. …

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Search Of S3 Ligo Data For Gravitational Wave Signals From Spinning Black Hole And Neutron Star Binary Inspirals, B. P. Abbott, R. Grosso, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres Jan 2008

Search Of S3 Ligo Data For Gravitational Wave Signals From Spinning Black Hole And Neutron Star Binary Inspirals, B. P. Abbott, R. Grosso, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on the methods and results of the first dedicated search for gravitational waves emitted during the inspiral of compact binaries with spinning component bodies. We analyze 788 hours of data collected during the third science run (S3) of the LIGO detectors. We searched for binary systems using a detection template family specially designed to capture the effects of the spin-induced precession of the orbital plane. We present details of the techniques developed to enable this search for spin-modulated gravitational waves, highlighting the differences between this and other recent searches for binaries with nonspinning components. The template bank we …

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Search For Gravitational Waves Associated With 39 Gamma-Ray Bursts Using Data From The Second, Third, And Fourth Ligo Runs, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres Jan 2008

Search For Gravitational Waves Associated With 39 Gamma-Ray Bursts Using Data From The Second, Third, And Fourth Ligo Runs, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We present the results of a search for short-duration gravitational-wave bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray satellite experiments during LIGO’s S2, S3, and S4 science runs. The search involves calculating the crosscorrelation between two interferometer data streams surrounding the GRB trigger time. We search for associated gravitational radiation from single GRBs, and also apply statistical tests to search for a gravitational-wave signature associated with the whole sample. For the sample examined, we find no evidence for the association of gravitational radiation with GRBs, either on a single-GRB basis or on a statistical basis. Simulating gravitational-wave bursts …

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Time Reversal, Brian E. Anderson, Michele Griffa, Paul A. Johnson, Carene Larmat, Timothy J. Ulrich Jan 2008

Time Reversal, Brian E. Anderson, Michele Griffa, Paul A. Johnson, Carene Larmat, Timothy J. Ulrich

Faculty Publications

This article provides an historical overview of Time Reversal (TR), introduces its basic physics, addresses advantages and limitations, and describes some applications of this very active research area of acoustics. In the Geophysics Group at the Los Alamos National Laboratory, we conduct studies of TR of elastic waves in solids. Our work includes application of TR to nondestructive evaluation of materials, as well as to earthquake source characterization, and ground-based nuclear explosion monitoring. We emphasize the term elastic waves here to underscore that we include both compression and shear waves, in contrast to purely acoustic waves that are only compressional.

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Determining The Refractive Index In The Extreme Ultraviolet Using Kramers-Kronig On Thin-Film Scandium Oxide Transmission Data, David D. Allred, Jacqualine J. Butterfield Jan 2008

Determining The Refractive Index In The Extreme Ultraviolet Using Kramers-Kronig On Thin-Film Scandium Oxide Transmission Data, David D. Allred, Jacqualine J. Butterfield

Faculty Publications

Whereas the real part of the refractive index is dependent on both transmittance and reflectance, the imaginary part can be determined from transmittance data alone. It is possible to use Kramers-Kronig analysis to calculate the real part if the imaginary part is known over a sufficiently broad range. We show that the delta calculated from reflection and transmission data without taking into account roughness may underestimate the real part of the refractive index of the scandium oxide samples we are studying by up to 40% near 270 eV.

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Taking Another Look: Light N-Capture Element Abundances In Metal-Poor Halo Stars, D. Burris, E. Jones, J. Lusk Jan 2008

Taking Another Look: Light N-Capture Element Abundances In Metal-Poor Halo Stars, D. Burris, E. Jones, J. Lusk

Journal of the Arkansas Academy of Science

Elements are produced in stars through a variety of processes; some are well known, others are still the object of active research. The elements Zirconium (Zr) and Yttrium (Y) are produced via neutron capture (ncapture). These elements reside in the mass range where there is uncertainty about the production mechanism at early time. The rapid n-capture process (r-process) was believed to be responsible for the production, but no study (Burris et al 2000, Gilroy et al 1988 and others) has been able to successfully use the r-process to reproduce the abundance signature for elements in this mass range for metal-poor …

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Equation Of State For A Van Der Waals Universe During Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev Jan 2008

Equation Of State For A Van Der Waals Universe During Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev

Articles

In a previous work [E.M. Prodanov, R.I. Ivanov and V.G. Gueorguiev, Reissner-Nordström expansion, Astropart. Phys. 27 (2007) 150], we proposed a classical model for the expansion of the Universe during the radiation-dominated epoch based on the gravitational repulsion of the Reissner-Nordström geometry — naked singularity description of particles that "grow" with the drop of the temperature. In this work we model the Universe during the Reissner-Nordström expansion as a van der Waals gas and determine the equation of state.

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Multi-Channel Digital Receiver Data Acquisition System For The Arecibo Radar System, Ryan Seal Jan 2008

Multi-Channel Digital Receiver Data Acquisition System For The Arecibo Radar System, Ryan Seal

Theses and Dissertations

Digital Receivers are commercially available, cost effective solutions that are becoming commonplace in modern data acquisition systems (MDAS). The digital receiver has the ability to be reconfigured via software, making MDAS flexible for a variety of applications. This thesis describes the design and implementation of a complete MDAS using a general purpose computer (GPC) equipped with a digital receiver card. This system will replace the older DAS (baseband sampling) used by the Space and Atmospheric Science (SAS) group at the Arecibo Observatory (AO). Emphasis is placed on a generic system easily adaptable to a specific application with minimal effort. A …

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Dielectronic Recombination And Stability Of Warm Gas In Active Galactic Nuclei, Susmita Chakravorty, Ajit K. Kembhavi, Martin Elvis, Gary J. Ferland, N. R. Badnell Jan 2008

Dielectronic Recombination And Stability Of Warm Gas In Active Galactic Nuclei, Susmita Chakravorty, Ajit K. Kembhavi, Martin Elvis, Gary J. Ferland, N. R. Badnell

Physics and Astronomy Faculty Publications

Understanding the thermal equilibrium (stability) curve may offer insights into the nature of the warm absorbers often found in active galactic nuclei. Its shape is determined by factors such as the spectrum of the ionizing continuum and the chemical composition of the gas. We find that the stability curves obtained under the same set of the above-mentioned physical factors, but using recently derived dielectronic recombination rates, give significantly different results, especially in the regions corresponding to warm absorbers, leading to different physical predictions. Using the current rates we find a larger probability of having a thermally stable warm absorber at …

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Editorial, First Science And Policy Issue, Jscas Jan 2008

Editorial, First Science And Policy Issue, Jscas

Journal of the South Carolina Academy of Science

No abstract provided.

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With The Help Of South Carolina Research Universities, Scra Demonstrates Leadership In Applied Research And Commercialization Within Sc, Bill Mahoney Jan 2008

With The Help Of South Carolina Research Universities, Scra Demonstrates Leadership In Applied Research And Commercialization Within Sc, Bill Mahoney

Journal of the South Carolina Academy of Science

No abstract provided.

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Sc Inbre: A Catalyst For Biomedical Research Development In South Carolina, Lucia A. Pirisi-Creek M.D, Scott Little, Ph.D. Jan 2008

Sc Inbre: A Catalyst For Biomedical Research Development In South Carolina, Lucia A. Pirisi-Creek M.D, Scott Little, Ph.D.

Journal of the South Carolina Academy of Science

No abstract provided.

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Phase-Dependent X-Ray Observations Of The Beta Lyrae System: No Eclipse In The Soft Band., Richard Ignace, L. Oskinova, W. Waldron, J. Hoffman, W.-R. Hamann Jan 2008

Phase-Dependent X-Ray Observations Of The Beta Lyrae System: No Eclipse In The Soft Band., Richard Ignace, L. Oskinova, W. Waldron, J. Hoffman, W.-R. Hamann

ETSU Faculty Works

Aims.We report on observations of the eclipsing and interacting binary beta Lyrae from the Suzaku X-ray telescope. This system involves an early B star embedded in an optically and geometrically thick disk that is siphoning atmospheric gases from a less massive late B II companion. Methods.Motivated by an unpublished X-ray spectrum from the Einstein X-ray telescope suggesting unusually hard emission, we obtained time with Suzaku for pointings at three different phases within a single orbit. Results.From the XIS detectors, the softer X-ray emission appears typical of an early-type star. What is surprising is the remarkably unchanging character …

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Cold Nuclear Matter Effects On J/Ψ Production As Constrained By Deuteron-Gold Measurements At Snn=200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, S. Rembeczki, Phenix Collaboration Jan 2008

Cold Nuclear Matter Effects On J/Ψ Production As Constrained By Deuteron-Gold Measurements At Snn=200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, S. Rembeczki, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

We present a new analysis of J/ψ production yields in deuteron-gold collisions at √sNN=200 GeV using data taken from the PHENIX experiment in 2003 and previously published in S. S. Adler et al. [Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/ψ data taken in 2005 are used to improve the baseline measurement and thus construct updated cold nuclear matter modification factors (RdAu). A suppression of J/ψ in cold nuclear matter is observed as one goes forward in rapidity (in the deuteron-going direction), corresponding to a region more sensitive to initial-state low-ₓ gluons in the gold nucleus. The …

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Constraining Convection Parameters From The Light Curve Shapes Of Pulsating White Dwarf Stars: The Cases Of Ec 14012-1446 And Wd 1524-0030, Gerald Handler, Judith L. Provençal, Michael H. Montgomery, Encarni Romero-Colmenero, Kaushar Sanchawala, Monika A. Lendl, Matt A. Wood, Isaac M. Silver, Paul G. Beck, Wenping Chen Jan 2008

Constraining Convection Parameters From The Light Curve Shapes Of Pulsating White Dwarf Stars: The Cases Of Ec 14012-1446 And Wd 1524-0030, Gerald Handler, Judith L. Provençal, Michael H. Montgomery, Encarni Romero-Colmenero, Kaushar Sanchawala, Monika A. Lendl, Matt A. Wood, Isaac M. Silver, Paul G. Beck, Wenping Chen

Aerospace, Physics, and Space Science Faculty Publications

Montgomery [1] developed a method to probe convection in pulsating white dwarf stars which allows the recovery of the thermal response time of the convection zone by fitting observed non sinusoidal light curves. He applied this method to two objects; the Whole Earth Telescope (WET) observed the pulsating DB white dwarf GD 358 for just this purpose. Given this WET run's success, it is time to extend Montgomery's method to pulsating DA white dwarf (ZZ Ceti) stars. We present observations of two ZZ Ceti stars, WD 1524 - 0030 and EC 14012 - 1446, both observed from multiple sites. EC …

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The Warps Survey. Vii. The Warps‐Ii Cluster Catalog, Donald J. Horner, Eric S. Perlman, Harald Ebeling, Laurence Jones, Caleb A. Scharf, Gary Wegner, Matthew Malkan, Ben Maughan Jan 2008

The Warps Survey. Vii. The Warps‐Ii Cluster Catalog, Donald J. Horner, Eric S. Perlman, Harald Ebeling, Laurence Jones, Caleb A. Scharf, Gary Wegner, Matthew Malkan, Ben Maughan

Dartmouth Scholarship

We present the galaxy cluster catalog from the second, larger phase of the Wide Angle ROSAT Pointed Survey (WARPS), an X-ray selected survey for high-redshift galaxy clusters. WARPS is among the largest deep X-ray cluster surveys and is being used to study the properties and evolution of galaxy clusters. The WARPS-II sample contains 125 clusters serendipitously detected in a survey of 301 ROSAT PSPC pointed observations and covers a sky area of 56.7 deg2. Of these 125 clusters, 53 have not been previously reported in the literature. We have nearly complete spectroscopic follow-up of the clusters, which range …

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First Results From Ideal 2-D Mhd Reconstruction: Magnetopause Reconnection Event Seen By Cluster, W. L. Teh, B. U. O. Sonnerup Jan 2008

First Results From Ideal 2-D Mhd Reconstruction: Magnetopause Reconnection Event Seen By Cluster, W. L. Teh, B. U. O. Sonnerup

Dartmouth Scholarship

We have applied a new reconstruction method (Sonnerup and Teh, 2008), based on the ideal single-fluid MHD equations in a steady-state, two-dimensional geometry, to a reconnection event observed by the Cluster-3 (C3) space- craft on 5 July 2001, 06:23 UT, at the dawn-side Northern- Hemisphere magnetopause. The event has been previously studied by use of Grad-Shafranov (GS) reconstruction, per- formed in the deHoffmann-Teller frame, and using the as- sumption that the flow effects were either negligible or the flow was aligned with the magnetic field. Our new method allows the reconstruction to be performed in the frame of reference moving …

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White Dwarf Luminosity And Mass Functions From Sloan Digital Sky Survey Spectra, Steven Degennaro, Ted Von Hippel, D. E. Winget, S. O. Kepler, Atsuko Nitta, Detlev Koester, Leandro Althaus Jan 2008

White Dwarf Luminosity And Mass Functions From Sloan Digital Sky Survey Spectra, Steven Degennaro, Ted Von Hippel, D. E. Winget, S. O. Kepler, Atsuko Nitta, Detlev Koester, Leandro Althaus

Publications

We present the first phase in our ongoing work to use Sloan Digital Sky Survey (SDSS) data to create separate white dwarf (WD) luminosity functions (LFs) for two or more different mass ranges. In this paper, we determine the completeness of the SDSS spectroscopic WD sample by comparing a proper-motion selected sample of WDs from SDSS imaging data with a large catalog of spectroscopically determined WDs. We derive a selection probability as a function of a single color (g − i) and apparent magnitude (g) that covers the range −1.0 < g − i < 0.2 and 15 < g < 19.5. We address the observed upturn in log g for WDs with Teff 12,000 K and offer arguments that the problem is limited to the line profiles and is not present in the continuum. We offer an empirical method of removing the upturn, recovering a reasonable mass function for WDs with Teff < 12,000 K. Finally we present a WD LF with nearly an order of magnitude (3358) more spectroscopically confirmed WDs than any previous work.

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Book Review: The Telescope: Its History, Technology, And Future, T. D. Oswalt Jan 2008

Book Review: The Telescope: Its History, Technology, And Future, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The Telescope : Its History, Technology, and Future by Geoff Andersen. Princeton, 2007 248p, 0691129797 $29.95, 9780691129792 $29.95.

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Book Review: Your Cosmic Context: An Introduction To Modern Cosmology, T. D. Oswalt Jan 2008

Book Review: Your Cosmic Context: An Introduction To Modern Cosmology, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Your Cosmic Context : an Introduction to Modern Cosmology by Todd Duncan and Craig Tyler Pearson Addison-Wesley, 2008 466p, 0132400103 $80.00, 9780132400107 $80.00.

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On Well-Balanced Schemes For Non-Equilibrium Flow With Stiff Source Terms, W. Wang, C.-W. Shu, Helen Yee Jan 2008

On Well-Balanced Schemes For Non-Equilibrium Flow With Stiff Source Terms, W. Wang, C.-W. Shu, Helen Yee

United States National Aeronautics and Space Administration: Publications

In the modeling of unsteady reactive problems, the interaction of turbulence with finiterate chemistry introduces a wide range of space and time scales, leading to additional numerical difficulties. A main difficulty stems from the fact that most numerical algorithms used in reacting flows were originally designed to solve non-reacting fluids. As a result, spatial stiffness due to reacting source terms and turbulence/chemistry interaction are major stumbling blocks to numerical algorithm development. One of the important numerical issues is the proper numerical treatment of a system of highly coupled stiff non-linear source terms, which will result in possible spurious steady state …

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Nanoscale Characterization Of Thin Film Coatings Using Annular Dark Field Scanning Transmission Electron Microscopy, Guillermo Acosta, Richard Vanfleet, David D. Allred Jan 2008

Nanoscale Characterization Of Thin Film Coatings Using Annular Dark Field Scanning Transmission Electron Microscopy, Guillermo Acosta, Richard Vanfleet, David D. Allred

Faculty Publications

When considering the optical performance of thin films in the Extreme Ultraviolet (EUV), developing an accurate physical description of a thin film coating is necessary to be able to successfully model optical performance. With the short wavelengths of the EUV, film interfaces and sample roughness warrant special attention and care. The surfaces of thin film samples are routinely measured by Atomic Force Microscopy, from which roughness can be determined. However, characterizing the quality of interfaces below the surface is much more challenging. In a recent study of scandium oxide thin films, High Resolution Transmission Electron Microscopy and Annular Dark Field …

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Denaturation Transition Of Stretched Dna, Andreas Hanke, Martha G. Ochoa, Ralf Metzler Jan 2008

Denaturation Transition Of Stretched Dna, Andreas Hanke, Martha G. Ochoa, Ralf Metzler

Physics & Astronomy Faculty Publications

We generalize the Poland-Scheraga model to consider DNA denaturation in the presence of an external stretching force. We demonstrate the existence of a force-induced DNA denaturation transition and obtain the temperature-force phase diagram. The transition is determined by the loop exponent c, for which we find the new value c=4ν−1/2 such that the transition is second order with c=1.85DNA, corresponding to a lower melting temperature T(F), in agreement with single-molecule DNA stretching experiments.

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Search For Gravitational Waves From Binary Inspirals In S3 And S4 Ligo Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres Jan 2008

Search For Gravitational Waves From Binary Inspirals In S3 And S4 Ligo Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on a search for gravitational waves from the coalescence of compact binaries during the third and fourth LIGO science runs. The search focused on gravitational waves generated during the inspiral phase of the binary evolution. In our analysis, we considered three categories of compact binary systems, ordered by mass: (i) primordial black hole binaries with masses in the range 0.35M⊙

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All-Sky Search For Periodic Gravitational Waves In Ligo S4 Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres Jan 2008

All-Sky Search For Periodic Gravitational Waves In Ligo S4 Data, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics & Astronomy Faculty Publications

We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50–1000 Hz and with the frequency’s time derivative in the range −1×10−8  Hz s−1 to zero. Data from the fourth LIGO science run (S4) have been used in this search. Three different semicoherent methods of transforming and summing strain power from short Fourier transforms (SFTs) of the calibrated data have been used. The first, known as StackSlide, averages normalized power from each SFT. A “weighted Hough” scheme is also developed and used, which also allows for a multi-interferometer search. The third method, …

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Kinetics And Thermodynamics Of Salt-Dependent T7 Gene 2.5 Protein Binding To Single- And Double-Stranded Dna., Leila Shokri, Boriana Marintcheva, Mootaz Eldib, Andreas Hanke, Ioulia Rouzina, Mark C. Williams Jan 2008

Kinetics And Thermodynamics Of Salt-Dependent T7 Gene 2.5 Protein Binding To Single- And Double-Stranded Dna., Leila Shokri, Boriana Marintcheva, Mootaz Eldib, Andreas Hanke, Ioulia Rouzina, Mark C. Williams

Physics & Astronomy Faculty Publications

Bacteriophage T7 gene 2.5 protein (gp2.5) is a single-stranded DNA (ssDNA)-binding protein that has essential roles in DNA replication, recombination and repair. However, it differs from other ssDNA-binding proteins by its weaker binding to ssDNA and lack of cooperative ssDNA binding. By studying the rate-dependent DNA melting force in the presence of gp2.5 and its deletion mutant lacking 26 C-terminal residues, we probe the kinetics and thermodynamics of gp2.5 binding to ssDNA and double-stranded DNA (dsDNA). These force measurements allow us to determine the binding rate of both proteins to ssDNA, as well as their equilibrium association constants to dsDNA. …

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Psr J1856+0245: Arecibo Discovery Of A Young Energetic Pulsar Coincident With The Tev G-Ray Source Hess J1857+026, J. W.T. Hessels, D. J. Nice, B. M. Gaensler, V. M. Kaspi, D. R. Lorimer, D. J. Champion, A. G. Lyne, M. Kramer, J. M. Cordes, P. C.C. Freire, Fredrick A. Jenet Jan 2008

Psr J1856+0245: Arecibo Discovery Of A Young Energetic Pulsar Coincident With The Tev G-Ray Source Hess J1857+026, J. W.T. Hessels, D. J. Nice, B. M. Gaensler, V. M. Kaspi, D. R. Lorimer, D. J. Champion, A. G. Lyne, M. Kramer, J. M. Cordes, P. C.C. Freire, Fredrick A. Jenet

Physics & Astronomy Faculty Publications

We present the discovery of the Vela-like radio pulsar J1856+0245 in the Arecibo PALFA survey. PSR J1856+0245 has a spin period of 81 ms, a characteristic age of 21 kyr, and a spin-down luminosity Ä– p 4.6 x 10 36 ergs s-1. It is positionally coincident with the TeV γ-ray source HESS J1857+026, which has no other known counterparts. Young, energetic pulsars create wind nebulae, and more than a dozen pulsar wind nebulae have been associated with very high energy (100 GeV-100 TeV) γ-ray sources discovered with the HESS telescope. The γ-ray emission seen from HESS J1857+026 is potentially produced …

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Testing The Nature Of S0 Galaxies Using Planetary Nebula Kinematics In Ngc 1023, E. Noordermeer, M. R. Merrifield, L. Coccato, M. Arnaboldi, M. Capaccioli, N. G. Douglas, K. C. Freeman, O. Gerhard, K. Kuijken, F. De Lorenzi, N. R. Napolitano, Aaron J. Romanowsky Jan 2008

Testing The Nature Of S0 Galaxies Using Planetary Nebula Kinematics In Ngc 1023, E. Noordermeer, M. R. Merrifield, L. Coccato, M. Arnaboldi, M. Capaccioli, N. G. Douglas, K. C. Freeman, O. Gerhard, K. Kuijken, F. De Lorenzi, N. R. Napolitano, Aaron J. Romanowsky

Faculty Publications

We investigate the manner in which lenticular galaxies are formed by studying their stellar kinematics: an S0 formed from a fading spiral galaxy should display similar cold outer disc kinematics to its progenitor, while an S0 formed in a minor merger should be more dominated by random motions. In a pilot study, an attempt to distinguish between these scenarios, we have measured the planetary nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the Planetary Nebula Spectrograph, we have detected and measured the line-of-sight velocities of 204 candidate planetary nebulae (PNe) in the field of this galaxy. Out …

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Stochastic Hard-Sphere Dynamics For Hydrodynamics Of Non-Ideal Fluids, Alejandro Garcia, A. Donev, B. J. Alder Jan 2008

Stochastic Hard-Sphere Dynamics For Hydrodynamics Of Non-Ideal Fluids, Alejandro Garcia, A. Donev, B. J. Alder

Faculty Publications

A novel stochastic fluid model is proposed with a nonideal structure factor consistent with compressibility, and adjustable transport coefficients. This stochastic hard sphere dynamics (SHSD) algorithm is a modification of the direct simulation Monte Carlo algorithm and has several computational advantages over event-driven hard-sphere molecular dynamics. Surprisingly, SHSD results in an equation of state and a pair correlation function identical to that of a deterministic Hamiltonian system of penetrable spheres interacting with linear core pair potentials. The fluctuating hydrodynamic behavior of the SHSD fluid is verified for the Brownian motion of a nanoparticle suspended in a compressible solvent.

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A Photometric Redshift Of Z = 1.8+0.4 -.3 For The Agile Grb 080514b, A. Rossi, A. De Ugarte Postigo, P. Ferrero, D. A. Kann, S. Klose, S. Schulze, J. Greiner, P. Schady, R. Filgas, E. E. Gonsalves, A. Küpcü Yolda¸S, T. Krühler, G. Szokoly, A. Yolda¸S, P. M.J. Afonso, C. Clemens, J. S. Bloom, D. A. Perley, J. P.U. Fynbo, A. J. Castro-Tirado, J. Gorosabel, P. Kubánek, Adria Updike, D. H. Hartmann, A. Giuliani, S. T. Holland, L. Hanlon, M. Bremer, J. French, G. Melady, D. A. García-Hernández Jan 2008

A Photometric Redshift Of Z = 1.8+0.4 -.3 For The Agile Grb 080514b, A. Rossi, A. De Ugarte Postigo, P. Ferrero, D. A. Kann, S. Klose, S. Schulze, J. Greiner, P. Schady, R. Filgas, E. E. Gonsalves, A. Küpcü Yolda¸S, T. Krühler, G. Szokoly, A. Yolda¸S, P. M.J. Afonso, C. Clemens, J. S. Bloom, D. A. Perley, J. P.U. Fynbo, A. J. Castro-Tirado, J. Gorosabel, P. Kubánek, Adria Updike, D. H. Hartmann, A. Giuliani, S. T. Holland, L. Hanlon, M. Bremer, J. French, G. Melady, D. A. García-Hernández

Arts & Sciences Faculty Publications

The AGILE gamma-ray burst GRB 080514B is the first detected to have emission above 30 MeV and an optical afterglow. However, no spectroscopic redshift for this burst is known.We report on our ground-based optical/NIR and millimeter follow-up observations of this event at several observatories, including the multi-channel imager GROND on La Silla, supplemented by Swift UVOT and Swift XRT data. The spectral energy distribution (SED) of the optical/NIR afterglow is found to decline sharply bluewards to the UV bands, which can be utilized in estimating the redshift. Fitting the SED from the Swift UVOT uvw2 band to the H band, …

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