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Differences in the O7+/O6+ ratio of magnetic cloud and non-cloud coronal mass ejections
Livi, S.; Woch, J.; Schwenn, R. +7 more
On its trajectory to Jupiter and over the poles of the Sun the Ulysses spacecraft has observed a considerable number of Coronal Mass Ejection (CME) transients in slow and in fast solar wind streams. The analysis of the magnetic field topology and the O7+/O6+ charge state ratio of 56 of these events has yielded strong evidence…
Dust, Gas, and the Evolutionary Status of the Radio Galaxy 8C 1435+635 at z = 4.25
Ivison, R. J.; Dunlop, J. S.; Stevens, J. A. +8 more
We present the results of new rest-frame far-IR observations of the z = 4.25 radio galaxy 8C 1435+635, which not only confirm that it contains an enormous quantity of dust (as first inferred from its millimeter-wave detection by Ivison in 1995), but also allow the first meaningful constraints to be placed on the mass of this dust and associated ga…
High-Resolution Observations of the Solar Hydrogen Lyman Lines in the Quiet Sun with the SUMER Instrument on SOHO
Wilhelm, K.; Mariska, J. T.; Warren, H. P.
We present high-resolution observations of the higher H Lyman series lines taken with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) experiment flown on the Solar and Heliospheric Observatory (SOHO) spacecraft. We have used systematic observations extending from disk center to the solar limb to compute average profiles for represe…
Galaxy surface brightness and size evolution to z~4
Im, M.; Griffiths, R. E.; Roche, N. +2 more
Using HST WFPC2 data, we estimate half-light radii, morphological classifications and rest-frame, blue-band absolute magnitudes for 270 galaxies with spectroscopic redshifts from z~0 to z=3.43, and 77 thought from their colours to be at 2.0<=z<=4.5. The mean blue-band surface brightness decreases by ~2 mag along the Hubble sequence from elli…
Coronal and Transition Region Structure in the RS Canum Venaticorum Binaries V711 Tauri, AR Lacertae, and II Pegasi. I. Data Analysis and Emission Measure Distributions
Jordan, C.; Griffiths, N. W.
We present a study of the transition regions and coronae of the RS CVn binaries V711 Tau, AR Lac, and II Peg. Archival data from the Extreme Ultraviolet Explorer (EUVE), International Ultraviolet Explorer (IUE), Goddard High-Resolution Spectrograph (GHRS), and a variety of X-ray telescopes have been analyzed and modeled. Emission measure distribut…
NICMOS 2 Micron Continuum and H2 Images of OMC-1
Schneider, Glenn; Chrysostomou, Antonio; Young, Erick T. +8 more
The core of OMC-1 has been imaged with the Near-Infrared Camera and Multiobject Spectrometer (NICMOS) on board the Hubble Space Telescope at 0.2" resolution in 1% filters at 2.12 and 2.15 µm, revealing intricate structures in both continuum and shocked molecular hydrogen line emission. Numerous H2-emitting clumps surrounding the B…
Toward a Realistic Diffusion Tensor for Galactic Cosmic Rays
Burger, R. A.; Hattingh, M.
We present analytical expressions for the mean free path parallel to the background magnetic field, calculated from quasi-linear theory for a composite slab/two-dimensional geometry model of turbulence. Diffusion perpendicular to the field is assumed to be anisotropic and proportional to parallel diffusion. For the variation in the magnetic field …
The beta Pictoris circumstellar disk. XXIV. Clues to the origin of the stable gas
Deleuil, M.; Spyromilio, J.; Feldman, P. D. +11 more
GHRS high resolution spectra of {beta \:Pictoris} were obtained to study the stable gas around this star. Several elements are detected and their abundances measured. Upper limits to the abundances of others are also measured. The data permit improved chemical analysis of the stable gas around {beta \:Pictoris}, and yield new and more accurate est…
Proper Motions in the Ejecta of η Carinae with a 50 Year Baseline
Smith, Nathan; Gehrz, Robert D.
Observations of η Carinae from three separate epochs spanning a total of 50 years are used to measure the proper motions of several easily identifiable features in the Homunculus Nebula. Our principal conclusion is that the equatorial features were ejected significantly after the ``Great Eruption,'' very likely in the outburst that occurred around…
Mode switching in the nearby Mira-like variable R Doradus
Bedding, T. R.; Jones, A.; Zijlstra, Albert A. +1 more
We discuss visual observations spanning nearly 70 years of the nearby semiregular variable R Doradus. Using wavelet analysis, we show that the star switches back and forth between two pulsation modes having periods of 332d and about 175d, the latter with much smaller amplitude. Comparison with model calculations suggests that the two modes are the…