Search Publications
Missions
Journals
Publication Years
The collision strength of the [Ne v] infrared fine-structure lines
Beintema, D. A.; Ferland, G. J.; van Hoof, P. A. M. +1 more
The calculation of accurate collision strengths for atomic transitions has been a long standing problem in quantitative spectroscopy. Most modern calculations are based on the R-matrix method and problems pertaining to the use of this method have led to a discussion of the accuracy of these results. More in particular, based on an analysis of the …
Star formation in distant starburst galaxies
Alloin, D.; Pastoriza, M. G.; Bonatto, C. +1 more
This paper discusses the stellar population content of distant (5 000 km s^{-1} <== V_R<=16 000 km s^{-1}) galaxies with enhanced star-formation activity. Distinction is made between isolated galaxies and galaxies morphologically disturbed, with clear signs of interaction such as mergers. In these galaxies the International Ultraviolet Explo…
The Local Interstellar Medium in Puppis-Vela
Blaauw, A.; Moos, H. Warren; Sahu, M. S. +1 more
The first study of the local interstellar medium (LISM) toward Puppis-Vela (l=245deg to 275°, b=-15deg to +5°, d<200 pc) is presented in this paper. A study of the locations, sizes, and physical characteristics of local interstellar gas, i.e.``astronephography,'' is included, and relies upon the improved distance measureme…
Emerging flux as a driver for homologous flares
Culhane, J. L.; Harra, L. K.; Matthews, S. A. +1 more
We present multi-wavelength observations of 2 M-class solar flares observed by SoHO and Yohkoh, which appear to be homologous. By examination of the flare loop morphology and footpoints we propose a schematic reconnection scenario of a two loop interaction in a quadrupolar magnetic configuration, for both flares (Machado ?; Mandrini ?). After the …
The discovery of photospheric nickel in the hot DO white dwarf REJ 0503-289
Werner, K.; Dreizler, S.; Barstow, M. A. +4 more
We present the first evidence for the direct detection of nickel in the photosphere of the hot DO white dwarf REJ 0503-289. While this element has been seen previously in the atmospheres of hot H-rich white dwarfs, this is one of the first similar discoveries in a He-rich object. Intriguingly, iron, which is observed to be more abundant than Ni in…
Lyα imaging of a very luminous z=2.3 starburst galaxy with WFPC2
Roche, Nathan; Lowenthal, James; Woodgate, Bruce
We investigate the Lyα and UV continuum morphology of one of the most luminous known Lymanα emitting galaxies (the `Coup Fourré Galaxy'), associated with a z=2.3 damped Lyα absorption system in the spectrum of the QSO PHL 957. The galaxy is observed with the Hubble Space Telescope Wide-Field Planetary Camera 2 (HST WFPC2), through a narrow filter …
Integral field spectroscopy of the radio galaxy 3C 171
Durret, F.; Petitjean, P.; Márquez, I. +1 more
We have performed integral field spectroscopy of the radio galaxy {3C 171} (redshift z=0.238) with the TIGER instrument at the Canada France Hawaii telescope in the Hβ -[OIII]4959-5007 wavelength region. We present the reconstructed Hβ and [OIII] images and compare them to the HST and radio maps. We discuss the variations of the [OIII]/Hβ line rat…
Rotational modulation and flares on RS CVn and BY Dra stars. XX. Photometry and spectroscopy of CC Eri in late 1989
Amado, P. J.; Doyle, J. G.; Mathioudakis, M. +4 more
The active flaring binary CC Eri was studied via multi-wavelength observations involving multi-based photometry and ground- and space-based spectroscopy. Combining early spectroscopic data with the present implies an orbital period of P=1.5615 days. Furthermore, the spectroscopic data suggests spectral types of K7 and M3 for the system. The optica…
Energetic proton observations at 1 and 5 AU: 1. January-September 1997
Lario, D.; Balogh, A.; Maksimovic, M. +6 more
We present energetic particle observations by the Ulysses and Wind spacecraft during the years 1997-1998. During this period, Ulysses moved from +19° to -19° in heliographic latitude with heliocentric distances ranging from 4.71 to 5.41 AU. Wind was located near the Earth at 1 AU from the Sun in the ecliptic plane. The proximity of Ulysses to the …
Studying the Pulsation of Mira Variables in the Ultraviolet
Wood, B. E.; Karovska, M.
We present results from an empirical study of the Mg II h and k emission lines of selected Mira variable stars, using spectra from the International Ultraviolet Explorer (IUE). The stars all exhibit similar Mg II behavior during the course of their pulsation cycles. The Mg II flux always peaks after optical maximum near pulsation phase φ=0.2-0.5, …