Search Publications
Large-scale distribution of galactic gamma radiation observed by COS-B
Caraveo, P. A.; Bignami, G. F.; Hermsen, W. +13 more
A complete survey of the Galaxy in high-energy gamma rays was performed aboard the ESA satellite COS-B. Gamma-ray maps were derived for energy ranges between 70 MeV and 5 GeV from 1975-1979, and are presented as both contour maps and as longitude and latitude profiles for three energy intervals. The spectral ratio is derived in the form of a color…
Atmospheric parameters and carbon abundance of white dwarfs of spectral types C2 and DC.
Koester, D.; Weidemann, V.; Zeidler, E. -M.
Model atmosphere calculations over a wide range of effective temperatures and carbon abundances are used to analyze IUE data obtained between 1200 and 3200 A as well as photometric and spectroscopic data in the visible region for several sets of white dwarfs of spectral types C2 and DC. The carbon abundances relative to helium are found to range f…
On the linearity of the SWP camera of the IUE : a correction algorithm.
Bohlin, R. C.; Cassatella, A.; Schiffer, F. H. +2 more
An algorithm is presented for correcting IUE low resolution spectral images obtained with the SWP camera for some of the non-linearity effects reported by Bohlin et al. (1980). The non-linearity problem, which affects SWP images processed at Goddard Space Flight Center in the period May 22, 1978 to July 7, 1979 and at VILSPA in the period June 14,…
Shell and photosphere of OMI ORI E : new observations and improved model.
Groote, D.; Hunger, K.
Phase-dependent IR fluxes in the J, H, K, L, and M bands, together with visual spectrograms and IUE spectra, are used to study the helium-rich star Sigma Ori E. An effective temperature of about 22,500 K is derived, along with an angular diameter of 0.079 milliarcsec, a surface gravity of log g equals 3.85, and a mass of approximately 3 solar mass…
Detection of further red giants with "Hybrid" atmospheres ANS a possible correlation with double circumstellar MGII and CAII lines.
Reimers, D.
In addition to the three known hybrid atmosphere stars (Alpha and Beta Aqr, and Alpha TrA), the three red giants (Theta Her, Iota Aur and Delta TrA) which have both transition layer lines (N V, C IV, Si IV, C II) and cool winds have been detected. It is shown that all six known hybrid stars have double circumstellar Ca II and Mg II absorption line…
COS-B gamma-ray measurements, cosmic rays and the local interstellar medium
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +7 more
A study of the relation between galaxy counts and gamma rays measured by the COS-B satellite clearly shows that there exists a bidimensional correlation between these quantities. Though the 21 cm measurements are more accurate than galaxy counts they show a weaker correlation with gamma rays. A significant fraction of the local gas in molecular fo…
The local interstellar medium as traced by gamma rays
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +8 more
Gamma-ray flux measurements (70-5000 MeV) made with the COS-B satellite have been used to study the distribution of total gas column density in the latitude range from 11 deg to 19 deg. A close correlation with the distribution found from galaxy counts exists. The dominant structure is associated with Gould's Belt, but several other major features…
Production of CS and S in Comet Bradfield /1979 X/
Feldman, P. D.; Jackson, W. M.; Halpern, J. B. +1 more
High and low resolution ultraviolet spectra of carbon monosulfide (CS) in Comet Bradfield (1979 X) were obtained with the IUE satellite. The high resolution rotational profile of the (0, 0) band at 257.5 nm can be fitted with a theoretical profile derived assuming a Boltzmann temperature of 70 K. Spatial plots of the low resolution data for both S…
IUE observations of dwarf novae during active phases.
Stahl, O.; Vogt, N.; Wolf, B. +4 more
Spectra of six dwarf novae during active phases were observed with the IUE in the low resolution mode in order to study different types of outburst behavior and to investigate physical processes during outbursts. Results were obtained for continuum energy distribution and interstellar extinction, temperatures and spectral indices, line spectra, an…
SK 143 : an SMC star with a galactic-type ultraviolet interstellar extinction.
Lequeux, J.; Prevot, L.; Prevot-Burnichon, M. -L. +2 more
The ultraviolet extinction curve (1200-3000 A) deduced from IUE observations of the Small Magellanic Cloud star Sk 143 is presented. This curve is rather similar to the galactic one, with a large bump at 2200 A and a smaller rise shortward of 2000 A compared to the SMC extinction curve of Rocca-Volmerange et al. (1981). The N(H)/E(B-V) ratio estim…