Search Publications
Experimental Pd II Oscillator Strengths and the Palladium Abundance in the HgMn-Type Star chi LUPI
Wahlgren, Glenn M.; Leckrone, David S.; Johansson, Sveneric G. +5 more
Experimental oscillator strengths for 19 ultraviolet lines of Pd II have been derived from measurements of line intensities in calibrated Fourier transform spectra, combined with picosecond-pulse laser measurements of radiative lifetimes. Five of these t9 lines, in addition to other Pd II lines, are present in Hubble Space Telescope/Goddard High-R…
Temperatures of Delta CEP and Nonvariable Supergiants
Evans, Nancy Remage; Teays, Terry J.
This study is a comparison of the energy distributions of nonvariable supergiants and δ Cep with model atmospheres. The data include lUE spectra from 1700 to 3200 A, and broadband B, V, RC, IC, J, H, and K. The model atmosphere comparisons cover a range of temperatures, gravities, and microturbulence. Both the nonvariables an…
The Inferred Redshift Distribution of the Faint Blue Galaxy Excess
Driver, Simon P.; Windhorst, Rogier A.; Phillipps, Steven +1 more
We infer the redshift distribution of the faint blue galaxy excess (FBE) at mB = 23.5 by subtracting the predicted distribution of giant/normal galaxies from the observed N(z) distribution for all types. This is possible because of the recent deep Hubble Space Telescope (HST) WFPC2 morphological number counts that have convincingly demonstrated th…
Possible Association of a Quiescent X-Ray Source with a Gamma-Ray Burster
Cline, T.; Hurley, K.; Kouveliotou, C. +10 more
We report on the first repeatedly detected statistically significant coincidence (chance probability ≈10-2-10-3) between an X-ray source and a gamma-ray burst error box. We present three ROSAT observations of the field of the gamma-ray burst of 1992 May 1. The first, a 2000 5 target of opportunity observation, was carried out…
A 2D Numerical Study of Explosive Events in the Solar Atmosphere
Inhester, B.; Innes, D.; Jin, S. -P.
Two-dimensional (2D) compressible magnetohydrodynamic simulations are performed to explore the idea that the asymmetric reconnection between newly emerging intranetwork magnetic field flux and pre-existing network flux causes the explosive events in the solar atmosphere. The dependence of the reconnection rate as a function of time on the density …
Far infrared mapping of the galaxies M51 and M101 with ISOPHOT.
Lemke, D.; Telesco, C. M.; Kinkel, U. +6 more
We present far infrared (FIR) images of the two nearby galaxies M 51 and M 101 at 60, 100, and at 175mum. These images resolve the spiral arms of the galaxies and a number of giant HII regions embedded therein.
Detection of Accreting, Circumstellar Gas in a lambda Bootis Star: 131 Tauri
England, M. N.; McCollum, B.; Grady, C. A. +3 more
We present IUE high-dispersion spectra of the lambda Boo star, 131 Tau (HD 38545), confirming the presence of shell spectral features and also providing the first detection of accreting, circumstellar gas in the spectrum of a lambda Boo star. Accreting gas can be followed in the mid-UV Fe II transitions to +80 km s-1 relative to the star. Circumst…
Phase Resolved UV Spectroscopy of RX J0019.8+2156
Gänsicke, B. T.; Beuermann, K.; de Martino, D.
We present orbital phase-resolved UV spectroscopy of the supersoft X-ray source RX J0019.8+2156 obtained with IUE in 1992-93. The UV and optical light curves show a quasi-sinusoidal orbital modulation with wavelength dependent amplitude and a deep secondary minimum at Φ∼0.6. The UV spectrum is of lower excitation than in other SSS. The various met…
Type III bursts observed simultaneously by Wind and Ulysses
Bougeret, J. -L.; Hoang, S.; Leblanc, Y. +1 more
We consider a period of five months when Ulysses was passing behind the Sun as viewed from Wind and measure the low frequency cutoffs flo and the local plasma frequency fp for 303 bursts seen by one, the other, or both spacecraft. The preliminary results are: 1) 68% of the bursts were seen on dynamic spectra of both spacecraf…
A novel method to measure the solar wind speed
Moncuquet, Michel; Issautier, Karine; Meyer-Vernet, Nicole +1 more
We propose a novel method to measure in situ the bulk speed of a space plasma. It is based on the analysis of the electrostatic field spectrum produced by the Doppler-shifted thermal fluctuations of the plasma ions which can be measured with a sensitive receiver at the terminals of a passive electric antenna. We present a preliminary application i…