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Visible and UV observations of the giant early-type members of the Large Magellanic Cloud.
Nandy, K.; Willis, A. J.; Wilson, R. +3 more
Visible and UV observations of a sample of LMC members with V greater than 14 mag are presented. The sample contains an O9V star and B0-B3 giants. Their flux distributions in the IUE range are found to be the same as those of Galactic giants. The effective temperatures and radii of the LMC members are determined by comparison with models.
High dispersion IUE observations of the planetary nebula NGC 3918.
Torres-Peimbert, S.; Peña, M.
The authors have measured absolute fluxes of the lines present in a IUE high dispersion short wavelength exposure of NGC 3918. The mean electron density derived is 5×103 cm-3, in agreement with previous determinations. An anomalous value of 1.2 ± 0.1 for the ratio λλ1239/1243 of N V is found. Its implications are discussed.
The Neutral Gas Toward HD 93206
Welsh, B. Y.; Thomas, C. K.
The Carina star HD 93206 has been observed at high resolution using the IUE satellite to study the neutral atomic inter-stellar absorption lines in this direction. A line profile fitting analysis has been carried out on these resonance lines to determine cloud component column densities. The state of ionization of these clouds is discussed in deta…
Observations of Supernova Explosions and Cosmic-Rays
Palumbo, G. G. C.
A summary of coordinated observations at various frequencies of two type II and three type I SNe is given. Since type II events emit radio and X-ray radiation in the early phases it is shown how one has data to estimate the Cosmic Ray output from these SNe.
The UV spectrum of PKS 2251+113 and physical conditions in the broad line region.
Dultzin-Hacyan, D.
The IUE satellite's UV spectrum of PKS 2251+113 is discussed, in view of previous IR, optical and X-ray observations which indicate that one cannot fit a single power law to the entire continuum. The values of the intensity ratios of Lyman-alpha to Balmer lines and Si II 1196/1263 indicate that PKS 2251+113 exemplifies objects for which the Broad …
The Age Decay of Stellar Magnetic Activity in MS Field Solar Type Stars
Vazquez, M.; Cabestany, J.
The age decay of two indicators of the stellar magnetic activity (λ 2800 MgII emission flux and λ 10830 HeI equivalent width) have been studied for field solar-type stars. The Li abundance has been used, in most of the cases, as a stellar age indicator. A calibrated decay law for MgII has been determined and compared with a similar one, recently p…
Diffuse Galactic Emission of High Energy Gamma Rays
Hartman, R. C.; Fichtel, C. E.; Kniffen, D. A.
A study of the gamma-radiation produced by the interaction of cosmic rays with the interstellar matter and photons is extended, based on recent COS-B satellite results and background estimates (1982) and evaluations of the 21-cm radiation in the Galaxy. Gamma-ray intensities predicted over the latitude range of -10 to 10 degrees for energy ranges …
COS-B measurements of high-latitude gamma rays and evidence for a component not related to the gas.
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +7 more
The gamma ray latitude distribution for absolute value of b between 10 deg and 90 deg measured by COS-B is compared with the expected emission from cosmic-ray/gas interactions. An additional component is found which is unrelated to the gas, and which may be interpreted as a gamma-ray 'halo'. The possibility of an inverse-Compton origin is discusse…
Variable mass-flux in Be stars
Doazan, V.; Thomas, R. N.
The available observational data concerning the variability of Be stars is briefly reviewed, and some different hypotheses concerning the origin of Be variability are examined. It is shown that variability in Be stars is not restricted to short time scales. In fact, long term variations (such as 'E/C' variations of the intensity of the emission co…
Far UV radiation in cataclysmic variables.
Drechsel, H.; Rahe, J.; Wargau, W.
The absolute continuum flux distributions in the far UV region of nine cataclysmic systems exhibit considerable excess radiation over the fluxes expected from steady-state optically thick accretion disk models. The UV continua can alternatively be interpreted as superposition of two blackbody sources: a hot (0.5 - 2×105K) component orig…