Search Publications
High-energy gamma-ray and hard X-ray observations of CYG X-3.
Strong, A. W.; Hermsen, W.; Pollock, A. M. T. +7 more
High-energy (70 MeV < E < 5 GeV) gamma-ray observations of Cyg X-3 by the ESA satellite COS-B and hard X-ray (14 keV < E < 140 keV) observations by the Leiden-MIT balloon experiment, Leimit, are presented. A comparison with, and a study of earlier results over the 14 decades in energy from 1 keV up to ≡1017eV indicates that …
Star formation in nuclei of SO/E galaxies.
Rocca-Volmerange, B.; Guiderdoni, B.
Spectra of nuclei for some lenticular and elliptical galaxies observed from the IUE satellite in the far-UV light are analyzed with the help of the IUE spectral atlases using an almost similar resolution for galaxies and stars, down to about 8A for a significant signal/noise ratio. In the 2500A-3150A wavelength range, all gas-poor galaxies show 'r…
Magnetic structure in cool stars. XIII - Appropriate units for the rotation-activity relation
Rutten, R. G. M.; Schrijver, C. J.
The paper compares relations between coronal and chromospheric emissions, and between activity and stellar rotation, in which the radiative emissions that measure the magnetic activity of cool stars are expressed in different units. The surface flux density appears to be the most suitable unit in which to express the radiative emission measuring s…
Photometric properties of SN 1987A and other sources in the same field.
Panagia, N.; Clavel, J.; Wamsteker, W. +5 more
The authors find that the UV flux of SN 1987A declines since the very first IUE observation at a rate which is faster at shorter wavelengths while the emission around 5100 Å increases slowly but steadily with time. Thus, the UV radiation dominates the overall emission at early phases but becomes completely negligible at later phases. Such an evolu…
EUV photometry of DA white dwarfs with EXOSAT.
Jordan, S.; Koester, D.; Brunner, H. +1 more
The authors present EXOSAT EUV observations for 9 white dwarfs of spectral type DA. These are analysed together with other observational data from the literature using theoretical model atmospheres. For 8 objects He/H abundance ratios and interstellar hydrogen column densities are obtained. The data for HZ 43 seem to contradict recent results of o…
Photometry and spectroscopy of the O-type variable HD 167971.
Stahl, O.; Leitherer, C.; Zickgraf, F. -J. +9 more
The authors present photometric and spectroscopic observations of the O-type variable HD 167971. From a period analysis of the visual light-curve they find P = 3.3213 days. Combining the photometric and spectroscopic data they derive a consistent model for the system which can be understood in terms of a close O-type eclipsing binary and a third, …
The anomalous ultraviolet spectrum of the AM HER star H 0538+608.
Bonnet-Bidaud, J. M.; Mouchet, M.
The X-ray source H 0538 + 608, recently identified as an AM Her system, was observed with the IUE satellite and discovered to have a unique ultraviolet spectrum. The strong resonance emission lines commonly observed in the AM Her sources are present but with very unusual intensities: the C IV line is notably weak while N V strongly dominates, with…
Rotational modulation and flares on RS CVn and BY DRA stars. IV. The spatially resolved chromosphere of AR Lacertae.
Linsky, J. L.; Gary, D. E.; Walter, F. M. +4 more
The authors observed the RS CVn system AR Lacertae systematically over an orbital period with the International Ultraviolet Explorer in October 1983. Contemporaneous radio observations were obtained at the Very Large Array. The spectra of the Mg II k emission line were analyzed using a Doppler imaging technique. In this way, the authors identified…
Macroscopic Perturbations of the IMF by p/ Halley as Seen by the Giotto Magnetometer
Neubauer, F. M.; Raeder, J.; Burlaga, L. F. +1 more
Giotto magnetic field data have been used to analyze the macroscopic field structure in the vicinity of comet P/Halley. During the Giotto flyby at P/Halley the IMF showed quite a stable "away" polarity. Draping of magnetic field lines is clearly observed along the outbound leg of the trajectory. Inside the magnetic pile-up region the field reverse…
Rotational modulation and flares on RS CVn and BY DRA systems. II. IUE observations of BY Draconis and AU Microscopii.
Doyle, J. G.; Linsky, J. L.; Simon, T. +6 more
The modulation of the strong chromospheric and transition region lines over one cycle of the optical light curves of BY Dra and AU Mic is studied using IUE observations. The IUE observations were made from October 2-5, 1981 and include 7 short wavelength (SW) spectra and 13 long wavelength (LW) spectra. The integrated line flux data reveal that fo…