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Spectrophotometry of early type supergiants in the Large Magellanic Cloud.
Nandy, K.; Houziaux, L.; Thompson, G. I. +1 more
A sample of LMC supergiants ranging in type from O5 to A1 has been subjected to equivalent width measurements of major stellar features in the visible and UV spectral regions, using methods that are entirely numerical and to the greatest possible degree free from subjective estimates. LMC member results are compared with those obtained for their g…
Ultraviolet Observations of Three Classical Novae during Early Stages of Decline
Drechsel, H.; Rahe, J.; Wargau, W.
We present IUE UV spectra of the three recent classical novae N Sgr 1982, N Ser 1983, and N Mus 1983, obtained during early decline, transitional stage, and nebular phase, respectively. The line spectra are discussed. Preliminary conclusions concerning CNO over-abundances, shell geometry, and speed classes are drawn.
The interstellar lines and the energetics of the inner Doradus nebulafrom the ultraviolet spectrum of R 136a.
Feitzinger, J. V.; Hanuschik, R. W.; Schmidt-Kaler, Th.
An IUE short and long wavelength absorption line spectrum (1150 - 3000 Å) of the central superluminous object in the 30 Doradus nebula, R 136a, is analysed. Radial velocities and equivalent widths of the Magellanic interstellar components are given. The Magellanic interstellar components fall into four well-separated groups. The same groups show u…
IUE ultraviolet observations of narrow absorption components in the spectrum of dzeta Puppis.
Prinja, R. K.
Detailed IUE ultraviolet observations of multiple absorption components, observed superimposed on the Si IV λλ1393.76, 1402.77 P Cygni resonance line doublet in the O4ef star ζ Puppis, are presented. These components are observed in 16 out of 21 spectra at ≡0.75 and 0.82 of the terminal velocity over a period of three years up to 1981 and are stat…
Optical and ultraviolet study of five stars in the Pleiades open cluster
Dufton, P. L.; Younan, K. F.
Optical and ultraviolet observations of five low-reddened stars in the Pleiades open cluster have been obtained with an echelle spectrograph and the IUE satellite. The observed interstellar absorption lines have been analysed with different cloud models to estimate interstellar gas abundances for each line-of-sight. These results have been discuss…
IUE detector saturation and the new 2800 Å absorption featre `discovered' by Karim, Hoyle, and Wickramasinghe
Savage, B. D.; Sitko, M. L.
The broad λ2800 Å absorption feature 'discovered' by Karim, Hoyle, and Wickramasingle is instrumental in origin. The feature is produced by IUE detector saturation effects in overexposed spectra.
The variable component of the NGC 4151 IUE spectrum : evidence foran expanding spherical emission shell.
Stoner, R.; Ptak, R.; Gregory, S.
The profile of the forbidden line of C III (1909) is the same in two pseudo-trailed, low-resolution SWP spectra of the nucleus of the Seyfert galaxy NGC 4151 obtained with the IUE in November 1980 and December 1982, respectively. In the 1980 spectrum, the C III forbidden line profile is also very nearly the same as that of the resonance line C IV …
Gamma rays from accreting matter onto collapsed objects
Giovannelli, F.; Karakula, S.; Tkaczyk, W.
In the spherical accretion onto massive objects, the matter may be heated up to temperatures as high as 1012 °K. In such a hot plasma, the thermal bremsstrahlung (e-e and e-p) and π° decay from inelastic collisions of protons are the main γ-ray sources. We determined the γ -ray production spectra from the π° decay and from bremsstrahlun…
Studies of high-latitude gamma rays
Strong, A. W.
COS-B gamma-ray data (70-5000 MeV) in the latitude range 10°< b <90° are compared with the expected emission from cosmic-ray interactions with interstellar gas. An additional component is found to be necessary to explain the latitude dependence of the emission. Two possible origins for this component are discussed: a gamma-ray halo around th…
Notes on the system TV Geminorum.
Underhill, A. B.
Low-resolution SWP spectra and high-resolution LWR spectra of the SRc variable star TV Gem have been studied. The available ultraviolet spectrophotometry and UBV photometry of the system can be interpreted in terms of the blended light from a B3.5 IV star and an M1 Iab star. The separation of the two stars is less than about 3 arc sec. Since the m…