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2006

Astrophysics and Astronomy

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Discovery Of Extensive Optical Emission Associated With The X-Ray Bright, Radio Faint Galactic Snr G156.2+5.7, Christopher L. Gerardy, Robert A. Fesen Dec 2006

Discovery Of Extensive Optical Emission Associated With The X-Ray Bright, Radio Faint Galactic Snr G156.2+5.7, Christopher L. Gerardy, Robert A. Fesen

Dartmouth Scholarship

We present wide‐field Hα images of the Galactic supernova remnant (SNR) G156.2+5.7 which reveal the presence of considerable faint Hα line emission coincident with the remnant's X‐ray emission. We also present low‐resolution optical spectra for a few representative emission regions. The outermost Hα emission consists largely of long and thin (unresolved), smoothly curved filaments of Balmer‐dominated emission presumably associated with the remnant's forward shock front. Patches of brighter Hα emission along the western, south‐central, and north‐eastern regions appear to be radiative shocked interstellar medium filaments like those commonly seen in SNRs, with relatively strong [O i]λλ6300, 6364 and [S ii]λλ6716, …

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Upper Bounds On The Low-Frequency Stochastic Gravitational Wave Background From Pulsar Timing Observations: Current Limits And Future Prospects, F. A. Jenet, G. B. Hobbs, W. Van Straten, R. N. Manchester, M. Bailes, J. P.W. Verbiest, R. T. Edwards, A. W. Hotan, J. M. Sarkissian, S. M. Ord Dec 2006

Upper Bounds On The Low-Frequency Stochastic Gravitational Wave Background From Pulsar Timing Observations: Current Limits And Future Prospects, F. A. Jenet, G. B. Hobbs, W. Van Straten, R. N. Manchester, M. Bailes, J. P.W. Verbiest, R. T. Edwards, A. W. Hotan, J. M. Sarkissian, S. M. Ord

Physics and Astronomy Faculty Publications and Presentations

Using a statistically rigorous analysis method, we place limits on the existence of an isotropic stochastic gravitational wave background using pulsar timing observations. We consider backgrounds whose characteristic strain spectra may be described as a power-law dependence with frequency. Such backgrounds include an astrophysical background produced by coalescing supermassive black-hole binary systems and cosmological backgrounds due to relic gravitational waves and cosmic strings. Using the best available data, we obtain an upper limit on the energy density per unit logarithmic frequency interval of ΩgSMBH[1/(8 yr)}h2 ≤ 1.9 × 10-8 for an astrophysical background that is 5 times more stringent than …

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Small-Scale Structures In Three-Dimensional Magnetohydrodynamic Turbulence, P. D. Mininni, A. G. Pouquet, D. C. Montgomery Dec 2006

Small-Scale Structures In Three-Dimensional Magnetohydrodynamic Turbulence, P. D. Mininni, A. G. Pouquet, D. C. Montgomery

Dartmouth Scholarship

We investigate using direct numerical simulations with grids up to 15363 points, the rate at which small scales develop in a decaying three-dimensional MHD flow both for deterministic and random initial conditions. Parallel current and vorticity sheets form at the same spatial locations, and further destabilize and fold or roll up after an initial exponential phase. At high Reynolds numbers, a self-similar evolution of the current and vorticity maxima is found, in which they grow as a cubic power of time; the flow then reaches a finite dissipation rate independent of the Reynolds number.

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On The Search For Transits Of The Planets Orbiting Gliese 876, Paul D. Shankland, Eugenio J. Rivera, Gregory Laughlin, D. L. Blank, A. Price, B. Gary, R. Bissinger, Frederick Ringwald, G. White, Gregory W. Henry, Padric Mcgee, Aaron S. Wolf, Brad Carter, S. Lee, James Biggs, Berto Monard, Michael C. B. Ashley Dec 2006

On The Search For Transits Of The Planets Orbiting Gliese 876, Paul D. Shankland, Eugenio J. Rivera, Gregory Laughlin, D. L. Blank, A. Price, B. Gary, R. Bissinger, Frederick Ringwald, G. White, Gregory W. Henry, Padric Mcgee, Aaron S. Wolf, Brad Carter, S. Lee, James Biggs, Berto Monard, Michael C. B. Ashley

Information Systems and Engineering Management Research Publications

We report the results of a globally coordinated photometric campaign to search for transits by the P ~ 30 day and P ~ 60 day outer planets of the three-planet system orbiting the nearby M dwarf Gl 876. These two planets experience strong mutual perturbations, which necessitate the use of a dynamical (four-body) model to compute transit ephemerides for the system. Our photometric data have been collected from published archival sources, as well as from our photometric campaigns that were targeted to specific transit predictions. Our analysis indicates that transits by planet c (P ~ 30 days) do not currently …

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The Mass Of The Black Hole In The Seyfert 1 Galaxy Ngc 4593 From Reverberation Mapping, Kelly D. Denney, Misty C. Bentz, Bradley M. Peterson, Richard W. Pogge, Edward M. Cackett, Matthias Dietrich, Jeffrey K. J. Fogel, Himel Ghosh, Keith D. Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii Dec 2006

The Mass Of The Black Hole In The Seyfert 1 Galaxy Ngc 4593 From Reverberation Mapping, Kelly D. Denney, Misty C. Bentz, Bradley M. Peterson, Richard W. Pogge, Edward M. Cackett, Matthias Dietrich, Jeffrey K. J. Fogel, Himel Ghosh, Keith D. Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii

Physics and Astronomy Faculty Research Publications

We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory. Cross-correlation analysis of the Hβ emission-line light curve with the optical continuum light curve reveals an emission-line time delay of τcent=3.73+/-0.75 days. By combining this time delay with the Hβ line width, we derive a central black hole mass of MBH=(9.8+/-2.1)×106 Msolar, an improvement in precision of a factor of several over past results.

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Iron In Hot Da White Dwarfs, Stéphane Vennes, Pierre Chayer, Jean François Dupuis, Thierry M. Lanz Dec 2006

Iron In Hot Da White Dwarfs, Stéphane Vennes, Pierre Chayer, Jean François Dupuis, Thierry M. Lanz

Aerospace, Physics, and Space Science Faculty Publications

We present a study of the iron abundance pattern in hot, hydrogen-rich (DA) white dwarfs. The study is based on new and archival far-ultraviolet spectroscopy of a sample of white dwarfs in the temperature range 30,000 K ≲ Teff ≲ 64,000 K. The spectra obtained with the Far Ultraviolet Spectroscopic Explorer, along with spectra obtained with the Hubble Space Telescope Imaging Spectrograph and the International Ultraviolet Explorer, sample Fe III-Fe VI absorption lines, enabling a detailed iron abundance analysis over a wider range of effective temperatures than previously afforded. The measurements reveal abundance variations in excess of 2 orders of …

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An Eccentric Hot Jupiter Orbiting The Subgiant Hd 185269, John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Gregory W. Henry, Jason T. Wright, Howard Isaacson, Chris Mccarthy Dec 2006

An Eccentric Hot Jupiter Orbiting The Subgiant Hd 185269, John Asher Johnson, Geoffrey W. Marcy, Debra A. Fischer, Gregory W. Henry, Jason T. Wright, Howard Isaacson, Chris Mccarthy

Information Systems and Engineering Management Research Publications

We report the detection of a Jupiter-mass planet in a 6.838 day orbit around the 1.28 M☉ subgiant HD 185269. The eccentricity of HD 185269b (e = 0.30) is unusually large compared to other planets within 0.1 AU of their stars. Photometric observations demonstrate that the star is constant to ±0.0001 mag on the radial velocity period, strengthening our interpretation of a planetary companion. This planet was detected as part of our radial velocity survey of evolved stars located on the subgiant branch of the H-R diagram—also known as the Hertzsprung gap. These stars, which have masses between 1.2 and …

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Optical Variability Of The Three Brightest Nearby Quasars, C. Martin Gaskell, Andrew J. Benker, Jeffrey S. Campbell, Thomas A. George, Cecilia H. Hedrick, Mary E. Hiller, Elizabeth S. Klimek, Joseph P. Leonard, Shoji Masatoshi, Bradley W. Peterson, Kelly S. Peterson, Kelly M. Sanders Dec 2006

Optical Variability Of The Three Brightest Nearby Quasars, C. Martin Gaskell, Andrew J. Benker, Jeffrey S. Campbell, Thomas A. George, Cecilia H. Hedrick, Mary E. Hiller, Elizabeth S. Klimek, Joseph P. Leonard, Shoji Masatoshi, Bradley W. Peterson, Kelly S. Peterson, Kelly M. Sanders

C. Martin Gaskell Publications

We report on the relative optical variability of the three brightest nearby quasars, 3C 273, PDS 456, and PHL 1811. All three have comparable absolute magnitudes, but PDS 456 and PHL 1811 are radio quiet. PDS 456 is a broadline object, but PHL 1811 could be classified as a high-luminosity Narrow-Line Seyfert 1 (NLS1). Both of the radio-quiet quasars show significant variability on a timescale of a few days. The seasonal rms V-band variability amplitudes of 3C 273 and PDS 456 are indistinguishable, and the seasonal rms variability amplitude of PHL 1811 was only exceeded by 3C 273 once in …

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Measurement Of The Spin-Orbit Alignment In The Exoplanetary System Hd 189733, Joshua N. Winn, John Asher Johnson, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt, Gregory W. Henry, Anna Roussanova, Matthew J. Holman, Keigo Enya, Norio Narita, Yasushi Suto, Edwin L. Turner Nov 2006

Measurement Of The Spin-Orbit Alignment In The Exoplanetary System Hd 189733, Joshua N. Winn, John Asher Johnson, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt, Gregory W. Henry, Anna Roussanova, Matthew J. Holman, Keigo Enya, Norio Narita, Yasushi Suto, Edwin L. Turner

Information Systems and Engineering Management Research Publications

We present spectroscopy of a transit of the exoplanet HD 189733b. By modeling the Rossiter-McLaughlin effect (the anomalous Doppler shift due to the partial eclipse of the rotating stellar surface), we find the angle between the sky projections of the stellar spin axis and orbit normal to be λ = -1fdg4 ± 1fdg1. This is the third case of a "hot Jupiter" for which λ has been measured. In all three cases λ is small, ruling out random orientations with 99.96% confidence, and suggesting that the inward migration of hot Jupiters generally preserves spin-orbit alignment.

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Ua1b1/7 Wku Centennial Mosaic Dedication, Western Kentucky University Nov 2006

Ua1b1/7 Wku Centennial Mosaic Dedication, Western Kentucky University

WKU Archives Records

Dedication program for the WKU Centennial Mosaic and fountain, includes sky map for Founders Day, November 16, 2006.

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A Reverberation-Based Mass For The Central Black Hole In Ngc 4151, Misty C. Bentz, Kelly D. Denney, Edward M. Cackett, Matthias Dietrich, Jeffery K. Fogel, Himel Ghosh, Keith Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Bradley M. Peterson, Richard W. Pogge, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii Nov 2006

A Reverberation-Based Mass For The Central Black Hole In Ngc 4151, Misty C. Bentz, Kelly D. Denney, Edward M. Cackett, Matthias Dietrich, Jeffery K. Fogel, Himel Ghosh, Keith Horne, Charles Kuehn, Takeo Minezaki, Christopher A. Onken, Bradley M. Peterson, Richard W. Pogge, Vladimir I. Pronik, Douglas O. Richstone, Sergey G. Sergeev, Marianne Vestergaard, Matthew G. Walker, Yuzuru Yoshii

Physics and Astronomy Faculty Research Publications

We have undertaken a new ground-based monitoring campaign to improve the estimates of the mass of the central black hole in NGC 4151. We measure the lag time of the broad Hβ line response compared to the optical continuum at 5100 Å and find a lag of 6.6+1.1-0.8 days. We combine our data with the recent reanalysis of UV emission lines by Metzroth and coworkers to calculate a weighted mean of the black hole mass, MBH=(4.57+0.57-0.47)×107 Msolar. The absolute calibration of the black hole mass is based on normalization of …

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Early-Time Chromatic Variations In The Wind-Swept Medium Of Grb 021211 And The Faintness Of Its Afterglow, M. C. Nysewander, D. E. Reichart, H.-S. Park, G. G. Williams, K. Kinugasa, D. Q. Lamb, A. A. Henden, S. Klose, T. Kato, A Harper, H Yamaoka, C Laws, K Torii, D G. York, J C. Barentine, J Dembicky, R J. Mcmillan, J A. Moran, Dieter H. Hartmann, B Ketzeback, M B. Bayliss, J A. Crain, A C. Foster, M Schwartz, P Holvorcem, P A. Price, R Canterna, G B. Crew, G R. Ricker, S D. Barthelmy Nov 2006

Early-Time Chromatic Variations In The Wind-Swept Medium Of Grb 021211 And The Faintness Of Its Afterglow, M. C. Nysewander, D. E. Reichart, H.-S. Park, G. G. Williams, K. Kinugasa, D. Q. Lamb, A. A. Henden, S. Klose, T. Kato, A Harper, H Yamaoka, C Laws, K Torii, D G. York, J C. Barentine, J Dembicky, R J. Mcmillan, J A. Moran, Dieter H. Hartmann, B Ketzeback, M B. Bayliss, J A. Crain, A C. Foster, M Schwartz, P Holvorcem, P A. Price, R Canterna, G B. Crew, G R. Ricker, S D. Barthelmy

Publications

We present Follow-Up Network for Gamma-Ray Bursts (FUN GRB) Collaboration observations of the optical afterglow of GRB 021211 made between 143 s and 102 days after the burst. Our unique data set includes the earliest filtered detections and color information for an afterglow in the pre-Swift era. We find that the afterglow is best described by (1) a propagation through a wind-swept medium, (2) a cooling break that is blueward of the observed optical frequencies, and (3) a hard electron energy distribution. However, superimposed on this ‘‘standard model’’ behavior we find, one and possibly two, significant chromatic variations during the …

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The Asymmetric Explosion Of Type Ia Supernovae As Seen From Near-Infrared Observations, Kentaro Motohara, Keiichi Maeda, Christopher L. Gerardy, Ken'ichi Nomoto, Masaomi Tanaka, Nozomu Tominaga, Takuya Ohkubo, Paolo A. Mazzali, Robert A. Fesen, Peter Hoflich, J. Craig Wheeler Nov 2006

The Asymmetric Explosion Of Type Ia Supernovae As Seen From Near-Infrared Observations, Kentaro Motohara, Keiichi Maeda, Christopher L. Gerardy, Ken'ichi Nomoto, Masaomi Tanaka, Nozomu Tominaga, Takuya Ohkubo, Paolo A. Mazzali, Robert A. Fesen, Peter Hoflich, J. Craig Wheeler

Dartmouth Scholarship

We present near-infrared spectra of late-phase (>200 days) Type Ia supernovae (SNe Ia) taken at the Subaru Telescope. The [Fe II] line of SN 2003hv shows a clear flat-topped feature, while that of SN 2005W shows a less prominent flatness. In addition, a large shift in their line center, varying from -3000 to 1000 km s-1 with respect to the host galaxies, is seen. Such a shift suggests the occurrence of an off-center, nonspherical explosion in the central region and provides important, new constraints on the explosion models of SNe Ia.

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Hd 71636, A Newly Discovered Eclipsing Binary, Gregory W. Henry, Francis C. Fekel, James R. Sowell, Joel S. Gearhart Nov 2006

Hd 71636, A Newly Discovered Eclipsing Binary, Gregory W. Henry, Francis C. Fekel, James R. Sowell, Joel S. Gearhart

Information Systems and Engineering Management Research Publications

Our differential BV photometric observations, acquired with an automated telescope at Fairborn Observatory, show that HD 71636 is an eclipsing binary. From follow-up red-wavelength spectroscopic observations we classify the primary and secondary as an F2 dwarf and an F5 dwarf, respectively. The system has a period of 5.01329 days and a circular orbit. We used the Wilson-Devinney program to simultaneously solve our BV light curves and radial velocities and determined a number of fundamental properties of the system. Comparison with evolutionary tracks indicates that both stars are well ensconced on the main sequence. The age of the system is about …

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Further Evidence For Variable Synchrotron Emission In Xte J1118+480 In Outburst, Robert I. Hynes, Edward L. Robinson, Kevin J. Pearson, Dawn M. Gelino, Wei Cui, Yongquan Xue, Matt A. Wood, Todd K. Watson, Don Earl Winget, Isaac M. Silver Nov 2006

Further Evidence For Variable Synchrotron Emission In Xte J1118+480 In Outburst, Robert I. Hynes, Edward L. Robinson, Kevin J. Pearson, Dawn M. Gelino, Wei Cui, Yongquan Xue, Matt A. Wood, Todd K. Watson, Don Earl Winget, Isaac M. Silver

Aerospace, Physics, and Space Science Faculty Publications

We present simultaneous multicolor infrared and optical photometry of the black hole X-ray transient XTE Jill 8+480 during its short 2005 January outburst, supported by simultaneous X-ray observations. The variability is dominated by short timescales, ∼10 s, although a weak superhump also appears to be present in the optical. The optical rapid variations, at least, are well correlated with those in X-rays. Infrared JHKS photometry, as in the previous outburst, exhibits especially large-amplitude variability. The spectral energy distribution (SED) of the variable infrared component can be fitted with a power law of slope α = -0.78 ± 0.07, where Fᵧ …

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Ordering Tendencies In The Binary Alloys Of Rh, Pd, Ir, And Pt: Density Functional Calculations, Gus L. W. Hart, Brian Kolb, Stefan Müller, David B. Botts Oct 2006

Ordering Tendencies In The Binary Alloys Of Rh, Pd, Ir, And Pt: Density Functional Calculations, Gus L. W. Hart, Brian Kolb, Stefan Müller, David B. Botts

Faculty Publications

The binary alloys of Rh, Pd, Ir, and Pt are important because of their high catalytic potential. We report in this paper that the Rh1-xIrx and Rh1-xPtx systems, long thought to phase separate at low temperatures, actually exhibit miscibility over the entire concentration and temperature range. We find low critical ordering temperatures, indicating that long-range order is unlikely to be observed experimentally. These results are compared with previous theoretical predications for the other binary alloys of Rh, Pd, Ir, and Pt and with calculations performed here on the Pt1-xIrx and Pd1-xIrx systems. We discuss these results and investigate the mechanisms …

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Radial Velocity Observations Of The Extended Lunar Sodium Tail, E. J. Mierkiewicz, M. Line, F. L. Roesler, R. J. Oliversen Oct 2006

Radial Velocity Observations Of The Extended Lunar Sodium Tail, E. J. Mierkiewicz, M. Line, F. L. Roesler, R. J. Oliversen

Physical Sciences - Daytona Beach

We report the first velocity resolved sodium 5889.950 Å line profile observations of the lunar sodium tail observed in the anti-lunar direction near new Moon. These observations were made on 29 March 2006, 27 April 2006 and 28 April 2006 from Pine Bluff (WI) observatory with a double etalon Fabry-Perot spectrometer at a resolving power of ∼80,000. The observations were made within 2–14 hours from new Moon, pointing near the anti-lunar point. The average observed radial velocity of the lunar sodium tail in the vicinity of the anti-lunar point for the three nights reported was 12.4 km s−1 (from …

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Spitzer White Dwarf Planet Limits, F. Mullally, Ted Von Hippel, D. E. Winget Oct 2006

Spitzer White Dwarf Planet Limits, F. Mullally, Ted Von Hippel, D. E. Winget

Publications

We present preliminary limits on the presence of planets around white dwarf stars using the IRAC photometer on the Spitzer space telescope. Planets emit strongly in the mid-infrared which allows their presence to be detected as an excess at these wavelengths. We place limits of 5 MJ for 8 stars assuming ages of 1 Gyr, and 10 MJ for 23 stars.We describe our survey, present our results and comment on approaches to improve our methodology.

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Spitzer Measurements Of Atomic And Molecular Abundances In The Type Iip Sn 2005af, Rubina Kotak, Peter Meikle, Monica Pozzo, Schuyler D. Van Dyk, Duncan Farrah, Robert Fesen, Alexei V. Filippenko, Ryan J. Foley, Claes Fransson, Christopher L. Gerardy, Peter A. Hoflich, Peter Lundqvist, Seppo Mattila, Jesper Sollerman, J. Craig Wheeler Oct 2006

Spitzer Measurements Of Atomic And Molecular Abundances In The Type Iip Sn 2005af, Rubina Kotak, Peter Meikle, Monica Pozzo, Schuyler D. Van Dyk, Duncan Farrah, Robert Fesen, Alexei V. Filippenko, Ryan J. Foley, Claes Fransson, Christopher L. Gerardy, Peter A. Hoflich, Peter Lundqvist, Seppo Mattila, Jesper Sollerman, J. Craig Wheeler

Dartmouth Scholarship

We present results based on mid-infrared (3.6-30 μm) observations with the Spitzer Space Telescope of the nearby Type IIP supernova 2005af. We report the first ever detection of the SiO molecule in a Type IIP supernova. Together with the detection of the CO fundamental, this is an exciting finding as it may signal the onset of dust condensation in the ejecta. From a wealth of fine-structure lines we provide abundance estimates for stable Ni, Ar, and Ne that, via spectral synthesis, may be used to constrain nucleosynthesis models.

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Casimir Forces And Non-Newtonian Gravitation, Roberto Onofrio Oct 2006

Casimir Forces And Non-Newtonian Gravitation, Roberto Onofrio

Dartmouth Scholarship

The search for non-relativistic deviations from Newtonian gravitation can lead to new phenomena signalling the unification of gravity with the other fundamental interactions. Various recent theoretical frameworks indicate a possible window for non-Newtonian forces with gravitational coupling strength in the micrometre range. The major expected background in the same range is attributable to the Casimir force or variants of it if dielectric materials, rather than conducting ones, are considered. Here we review the measurements of the Casimir force performed so far in the micrometre range and how they determine constraints on non-Newtonian gravitation, also discussing the dominant sources of false …

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Measurements And Analysis Of Helium-Like Triplet Ratios In The X-Ray Spectra Of O-Type Stars, M. A. Leutenegger, F. B.S. Paerels, S. M. Kahn, David H. Cohen Oct 2006

Measurements And Analysis Of Helium-Like Triplet Ratios In The X-Ray Spectra Of O-Type Stars, M. A. Leutenegger, F. B.S. Paerels, S. M. Kahn, David H. Cohen

Physics & Astronomy Faculty Works

We discuss new methods of measuring and interpreting the forbidden-to-intercombination line ratios of heliumlike triplets in the X-ray spectra of O- type stars, including accounting for the spatial distribution of the X-ray-emitting plasma and using the detailed photospheric UV spectrum. Measurements are made for four O stars using archival Chandra HETGS data. We assume an X- ray-emitting plasma spatially distributed in the wind above some minimum radius R-0. We find minimum radii of formation typically in the range of 1.25 < R-0 / R-* < 1.67, which is consistent with results obtained independently from line profile fits. We find no evidence for anomalously low f / i ratios, and we do not require the existence of X-ray-emitting plasmas at radii that are too small to generate sufficiently strong shocks.

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The P14 Fusion-Associated Small Transmembrane (Fast) Protein Effects Membrane Fusion From A Subset Of Membrane Microdomains, Jennifer A. Corcoran, Jayme Salsman, Roberto De Antueno, Ahmed Touhami, Manfred H. Jericho, Eileen K. Clancy, Roy Duncan Oct 2006

The P14 Fusion-Associated Small Transmembrane (Fast) Protein Effects Membrane Fusion From A Subset Of Membrane Microdomains, Jennifer A. Corcoran, Jayme Salsman, Roberto De Antueno, Ahmed Touhami, Manfred H. Jericho, Eileen K. Clancy, Roy Duncan

Physics and Astronomy Faculty Publications and Presentations

The reovirus fusion-associated small transmembrane (FAST) proteins are a unique family of viral membrane fusion proteins. These nonstructural viral proteins induce efficient cell-cell rather than virus-cell membrane fusion. We analyzed the lipid environment in which the reptilian reovirus p14 FAST protein resides to determine the influence of the cell membrane on the fusion activity of the FAST proteins. Topographical mapping of the surface of fusogenic p14-containing liposomes by atomic force microscopy under aqueous conditions revealed that p14 resides almost exclusively in thickened membrane microdomains. In transfected cells, p14 was found in both Lubrol WX-and Triton X-100-resistant membrane complexes. Cholesterol depletion …

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The Young Open Cluster Ngc 2129, Giovanni Carraro, Brian Chaboyer, James Perencevich Oct 2006

The Young Open Cluster Ngc 2129, Giovanni Carraro, Brian Chaboyer, James Perencevich

Dartmouth Scholarship

The first charge‐coupled device UBV(RI)C photometric study in the area of the doubtful open cluster NGC 2129 is presented. Photometry of a field offset 15 arcmin northwards is also provided, to probe the Galactic disc population towards the cluster. Using star counts, proper motions from the UCAC2 catalogue, colour–magnitude and colour–colour diagrams, we demonstrate that NGC 2129 is a young open cluster. The cluster radius is 2.5 arcmin, and across this region we find evidence of significant differential reddening, although the reddening law seems to be normal towards its direction. Updated estimates of the cluster fundamental …

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Detection Of Diffuse Interstellar [O Ii] Emission From The Milky Way Using Spatial Heterodyne Spectroscopy, E. J. Mierkiewicz, R. J. Reynolds, F. L. Roesler, J. M. Harlander, K. P. Jaehnig Oct 2006

Detection Of Diffuse Interstellar [O Ii] Emission From The Milky Way Using Spatial Heterodyne Spectroscopy, E. J. Mierkiewicz, R. J. Reynolds, F. L. Roesler, J. M. Harlander, K. P. Jaehnig

Physical Sciences - Daytona Beach

Using a newly developed spatial heterodyne spectrometer (SHS), we have obtained the first radial velocity resolved emission-line profiles of diffuse [O II] 3726 and 3729 angstrom emission lines from the warm (10,000 K) ionized component of our Galaxy's interstellar medium. These [O II] lines are a principal coolant for this widespread, photoionized gas and are a potential tracer of variations in the gas temperature resulting from unidentified heating processes that appear to be acting within the Galaxy's disk and halo. By spectrally isolating for the first time Galactic [O II] from atmospheric [O II] emission, we were able to detect …

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Cross Sections Fall 2006, Department Of Physics And Astronomy Oct 2006

Cross Sections Fall 2006, Department Of Physics And Astronomy

Cross Sections

No abstract provided.

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Cooling Of The Quasi-Persistent Neutron Star X-Ray Transients Ks 1731-260 And Mxb 1659-29, Edward M. Cackett, Rudy Wijnands, Manuel Linares, Jon M. Miller, Jeroen Homan, Walter H. G. Lewin Oct 2006

Cooling Of The Quasi-Persistent Neutron Star X-Ray Transients Ks 1731-260 And Mxb 1659-29, Edward M. Cackett, Rudy Wijnands, Manuel Linares, Jon M. Miller, Jeroen Homan, Walter H. G. Lewin

Physics and Astronomy Faculty Research Publications

We present Chandra and XMM-Newton X-ray observations that monitor the neutron star cooling of the quasi-persistent neutron star X-ray transients KS 1731-260 and MXB 1659-29 for approximately 4 yr after these sources returned to quiescence from prolonged outbursts. In both sources the outbursts were long enough to significantly heat the neutron star crust out of thermal equilibrium with the core. We analyse the X-ray spectra by fitting absorbed neutron star atmosphere models to the observations. The results of our analysis strengthen the preliminary findings of Wijnands et al. that in both sources the neutron star crust cools down very rapidly …

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The Grb 060218/Sn 2006aj Event In The Context Of Other Gamma-Ray Burst Supernovae, P. Ferreo, D. A. Kann, A. Zeh, S. Klose, E. Pian, E. Palazzi, N. Masetti, Dieter H. Hartmann, J. Sollerman, J. Deng, A V. Filippenko, J Greiner, M A. Hughes, P Mazzali, W Li, E Rol, R J. Smith, N R. Tanvir Oct 2006

The Grb 060218/Sn 2006aj Event In The Context Of Other Gamma-Ray Burst Supernovae, P. Ferreo, D. A. Kann, A. Zeh, S. Klose, E. Pian, E. Palazzi, N. Masetti, Dieter H. Hartmann, J. Sollerman, J. Deng, A V. Filippenko, J Greiner, M A. Hughes, P Mazzali, W Li, E Rol, R J. Smith, N R. Tanvir

Publications

The supernova SN 2006aj associated with GRB 060218 is the second-closest GRB-SN observed to date (z =0.033). We present Very Large Telescope, Liverpool Telescope, and Katzman Automatic Imaging Telescope multi-color photometry of SN 2006aj. This super-nova is found to be subluminous and rapidly evolving. Its early light curve includes an additional wavelength-dependent component, which can be interpreted as shock break-out. We compare the photometric evolution of multi-band light curves with the corresponding properties of the present sample of more than 10 GRB-SNe with precisely known redshifts. Using host-galaxy extinction measure-ments, we derive extinction-corrected GRB-SN luminosities and place SN 2006aj in …

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Cluster Observations Of Reconnection Due To The Kelvin-Helmholtz Instability At The Dawnside Magnetospheric Flank, K. Nykyri, A. Otto, B. Lavraud, C. Mouikis, L. M. Kistler, A. Balogh, H. Rème Oct 2006

Cluster Observations Of Reconnection Due To The Kelvin-Helmholtz Instability At The Dawnside Magnetospheric Flank, K. Nykyri, A. Otto, B. Lavraud, C. Mouikis, L. M. Kistler, A. Balogh, H. Rème

Publications

On 3 July 2001, the four Cluster satellites traversed along the dawnside magnetospheric flank and observed large variations in all plasma parameters. The estimated magnetopause boundary normals were oscillating in the z-direction and the normal component of the magnetic field showed systematic ~2–3 min bipolar variations for 1 h when the IMF had a small positive bz-component and a Parker-spiral orientation in the x, y-plane. Brief ~33 s intervals with excellent deHoffman Teller frames were observed satisfying the Wal´en relation. Detailed comparisons with 2- D MHD simulations indicate that Cluster encountered rotational discontinuities generated by Kelvin-Helmholtz instability. We estimate a …

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Random Flows And Diagnostics Of Turbulence In The High Latitude Cirrus, Steven N. Shore, Ted N. Larosa, Raymond J. Chastain, Loris Magnani Oct 2006

Random Flows And Diagnostics Of Turbulence In The High Latitude Cirrus, Steven N. Shore, Ted N. Larosa, Raymond J. Chastain, Loris Magnani

Faculty and Research Publications

Aims: We present an analysis of the exceptionally turbulent velocity field in the high Galactic latitude cirrus cloud MBM 3. As in the other translucent clouds in our study (MBM 16 and MBM 40), there is no evidence for internal star formation. However, the large scale velocity variation in this cloud is more pronounced. Methods: We have mapped the cloud in 12CO and 13CO (1-0) at high spatial (0.03 pc) and velocity (0.06 km s-1) resolution. We constructed several velocity probability density functions (PDFs), estimated the turbulent transfer rate, and analyzed the linewidths as a function of the size of …

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Hd 131861, A Double-Line Spectroscopic Triple System, Francis C. Fekel, Gregory W. Henry, David J. Barlow, Dimitri Pourbaix Sep 2006

Hd 131861, A Double-Line Spectroscopic Triple System, Francis C. Fekel, Gregory W. Henry, David J. Barlow, Dimitri Pourbaix

Information Systems and Engineering Management Research Publications

Our red-wavelength spectroscopic observations of HD 131861, a previously known single-line multiple system, span 20 years. Now lines of two components, the short-period F5 V primary and G8 V secondary, have been detected. The inner orbit is circular with a period of 3.5507439 days, while the outer orbit of the system has a period of 1642 days or 4.496 yr and a relatively low eccentricity of 0.10. Analysis of the Hipparcos data produces a well-determined astrometric orbit for the long-period system that has an inclination of 52°. Our photometric observations show shallow primary and secondary eclipses of the short-period pair, …

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