Search Publications
Evidence against a redshift z > 6 for the galaxy STIS123627+621755
Dey, Arjun; Stanford, S. A.; Spinrad, Hyron +5 more
The identification of galaxies at extreme distances provides the most direct information about the earliest phases of galaxy formation. But at redshifts z > 5 even the most luminous galaxies appear faint; the interpretation of low signal-to-noise ratio data is difficult and misidentifications do occur. Here we report optical and near-infrared o…
Flare- and coronal mass ejection (CME)-associated type II bursts and related radio emissions
Vourlidas, Angelos; Leblanc, Yolande; Dulk, George A. +1 more
We report on two events that occurred within 6 hours of each other on November 3, 1997. They were observed with ground-based spectrographs in the meter to decameter range and with the WAVES experiment on the Wind spacecraft at longer wavelengths. Complementary observations were made with Extreme Ultraviolet Imaging Telescope (EIT) and Large Angle …
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…