Search Publications
Discovery of the `missing' mode in HR1217 by the Whole Earth Telescope
Kepler, S. O.; Kawaler, S. D.; Winget, D. E. +35 more
HR1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of non-radial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of 33.3 and 34.6µHz, with a sixth mode at a problematic spacing of 50.0µHz (which equals to the high-frequency side. As…
Comparative Analysis of GALLEX-GNO Solar Neutrino Data and SOHO/MDI Helioseismology Data: Further Evidence for Rotational Modulation of the Solar Neutrino Flux
Sturrock, Peter A.; Weber, Mark A.
Recent histogram analysis of GALLEX-GNO and SAGE data indicates that the solar neutrino flux, in the energy range of gallium experiments, varies on a timescale of weeks. Such variability could be caused by modulation of the neutrino flux by an inhomogeneous magnetic field in the solar interior if neutrinos have a nonzero magnetic moment. We may th…
Abundances and Physical Conditions in the Interstellar Gas toward HD 192639
York, D. G.; Sonnentrucker, P.; Welty, D. E. +2 more
We present a study of the abundances and physical conditions in the interstellar gas toward the heavily reddened star HD 192639 [E(B-V)=0.64], based on analysis of Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra covering the range from 912 to 1361 Å. This work constit…
Resolving the Buried Starburst in Arp 299
Charmandaris, V.; Stacey, G. J.; Gull, G.
We present new 37.7 µm far-infrared imaging of the infrared luminous (LIR~5.16×1011Lsolar) interacting galaxy Arp 299 (= IC 694 + NGC 3690). We show that the 38 µm flux, like the 60 and 100 µm emission, traces the luminosity of star forming galaxies but at considerably higher spatial resolution. O…
Hubble Space Telescope Spectroscopy of the Nucleus of M33
Long, Knox S.; Dubus, Guillaume; Charles, Philip A.
We have used the Hubble Space Telescope to obtain moderate resolution 1150-5700 Å spectroscopy of the nucleus of M33 and a blue star ~1" north-northwest of the nucleus in an attempt to find the optical counterpart of the nuclear X-ray source and to characterize stellar populations in the nuclear region. The Space Telescope Imaging Spectrograph spe…
Tomographic Separation of Composite Spectra. VIII. The Physical Properties of the Massive Compact Binary in the Triple Star System HD 36486 (δ Orionis A)
Gies, Douglas R.; Penny, Laura R.; Bagnuolo, William G., Jr. +2 more
We present the first double-lined spectroscopic orbital elements for the central binary in the massive triple δ Orionis A. The solutions are based on fits of cross-correlation functions of IUE high-dispersion UV spectra and He I λ6678 profiles. The orbital elements for the primary agree well with previous results, and in particular, we confirm the…
Chandra X-Ray Observatory Observation of A1689: New Determination of Mass Distribution and Comparison to Lensing Measurements
Wu, Xiang-Ping; Xue, Sui-Jian
We present a new estimate of the projected X-ray mass of A1689 observed with Chandra X-Ray Observatory, in an attempt to clarify the issue of whether or not there exists a discrepancy between X-ray and gravitational lensing mass estimates claimed in previous investigations based on Einstein, ROSAT, and ASCA observations. Particular attention is pa…
Localizing Width and Energy of Solar Global p-Modes
Howe, R.; Komm, R.; Hill, F.
We present the first attempt at localizing in latitude the temporal variation of mode energy, energy supply rate, and lifetime of global acoustic modes. We use Global Oscillation Network Group (GONG) and Michelson Doppler Imager data analyzed with the GONG peak-fitting algorithm to measure mode width and amplitude of individual (l, n, m) modes. Wh…
PMN J1632-0033: A New Gravitationally Lensed Quasar
Winn, Joshua N.; Kochanek, Christopher S.; Morgan, Nicholas D. +6 more
We report the discovery of a gravitationally lensed quasar resulting from our survey for lenses in the southern sky. Radio images of J1632-0033 with the Very Large Array and the Australia Telescope Compact Array exhibit two compact, flat-spectrum components with separation 1.47" and flux density ratio 13.2. Images with the Hubble Space Telescope r…
Effects of the heliospheric interface on the interplanetary Lyman alpha glow seen at 1 AU from the Sun
Izmodenov, V.; Quémerais, E.
This work presents multiple scattering computations of interplanetary background line profiles using Angle Dependent Partial Frequency Redistribution to model the scattering process as explained by Quémerais (\cite{Quemerais00}). The density and velocity distribution of hydrogen atoms in the heliosphere was computed using a self-consistent model o…