Science Archives Publication System

High energy gamma-rays from cygnus X-3

DOI: 10.1016/0275-1062(89)90036-2 Bibcode: 1989ChA&A..13..383L

Wu, Mei; Li, Tipei

Simultaneous observations by the ESA satellite COS-B show that the 2-12 keV X-rays and 150-5000 MeV gamma-rays of Cyg X-3 are negatively correlated. A clear gamma-ray image of Cyg X-3 can be obtained between June 1977 and June 1980, when the X-ray emission was low, to yield a flux of P(E > 100MeV) ~ 1 × 10 ^-6cm ^-2s ^-1…

1989 • Chinese Astronomy and Astrophysics

COS-B 2

In situ exploration of the dusty coma of comet P/Halley at Giotto's encounter: Nucleus emission and production rates from temporal variability

DOI: 10.1016/0273-1177(89)90274-3 Bibcode: 1989AdSpR...9c.273P

McDonnell, J. A. M.; Pankiewicz, G. S.; Perry, C. H.

Flux-time profiles from the DIDSY and PIA experiments, taken at Giotto's encounter with comet P/Halley, are used to study coma dust dynamics and the nucleus emission. A comparison of the data with a `fountain' model, incorporating variable source function and grain type is made. Local enhancements such as jets, envelopes and terminators are analys…

1989 • Advances in Space Research

Giotto 2

The VV Cephei Star V641 Cassiopeiae

DOI: 10.1086/115029 Bibcode: 1989AJ.....97..836S

Guinan, Edward F.; Shaw, J. Scott

Ultraviolet spectra of the variable star V641 Cas taken with the IUE satellite have confirmed the VV Cephei nature of this object. The observations are consistent with the variable being a M3 I + B2 V-III system with E(B-V) = 0.55 mag lying in the Perseus arm of the Galaxy. In spite of V641 Cas having the largest light variation in the visible of …

1989 • The Astronomical Journal

IUE 1

Giotto Comet Halley Dust Impact experiment: Studies of discrete impact events

DOI: 10.1016/0273-1177(89)90276-7 Bibcode: 1989AdSpR...9c.281A

McDonnell, J. A. M.; Alexander, W. M.; Goad, H. +2 more

Analysis of discrete pulse height data from specific individual events of the Giotto Comet Halley Dust Impact Detectors DID-1 and DID-4 has been completed. The cumulative flux for the mid-size range of this Giotto comet dust experiment has been studied and results are presented. The technique employed in the investigation utilized a constant numbe…

1989 • Advances in Space Research

Giotto 1

Ultraviolet studies of the interstellar gas in the direction of the stars AE Aur (09.5V) andθ ² Ori A (09.0V)

DOI: 10.1007/BF00648381 Bibcode: 1989Ap&SS.151..227A

Avcioglu, Kamuran; Mentese, H. Huseyin

We have studied high-resolution SWP spectra of AE Aur andθ² Ori A, obtained from the International Ultraviolet Explorer Satellite; and derived curve of growth and column densities ofCII,CII^*, AlII, SiII, SiII^*,SII, CrII, FeII, NiII, and ZnII. It has been possible to fit these ions on one empirical curve of growth w…

1989 • Astrophysics and Space Science

IUE 1

A correlation of energetic particle flux anisotropies with magnetic field variations in- and outside the coma of comet Halley

DOI: 10.1016/0273-1177(89)90286-X Bibcode: 1989AdSpR...9c.343K

Neubauer, F. M.; Daly, P. W.; Ip, W. -H. +4 more

Anisotropies and energy spectra of cometary ions (mainly O⁺, OH⁺, H₂O⁺) derived from the EPA/EPONA measurements on board of Giotto during the encounter (12-14 March 1986) with comet Halley are used to study the acceleration processes taking place in the vicinity of the comet. Further evidence was found f…

1989 • Advances in Space Research

Giotto 1

An Interpretation of the Line Profile Variations in the IUE Spectrum of the Wolf-Rayet Binary gamma 2 Velorum: Erratum

DOI: 10.1086/168146 Bibcode: 1989ApJ...347..561B

Sahade, Jorge; Brandi, Estela; Ferrer, Osvaldo

1989 • The Astrophysical Journal

IUE 1

An upper limit on the high-energy gamma-ray emission of VELA X-1.

Bibcode: 1989A&A...226..145M

Kanbach, G.; Oegelman, H.; Mattox, J. R.

The possibility of high-energy gamma-ray emission from the X-ray binary Vela X-1 was investigated by analyzing the COS-B satellite observations, using the COS-B X-ray detector for a phase coherent analysis in the search of rotational periodicity. The rotational upper limit is compared to the X-ray, TeV, and PeV fluxes reported by Chodil et al. (19…

1989 • Astronomy and Astrophysics

COS-B 1

IUE Spectra of HD 269665 (Sk -68 110), a Hot Subdwarf in the Direction of the Large Magellanic Cloud

DOI: 10.1086/115034 Bibcode: 1989AJ.....97..881H

Hill, Robert S.; Smith, Andrew M.

Comparison of high- and low-resolution IUE spectra of HD 269665 (Sanduleak -68 deg 110) show that the star is a subdwarf with a temperature in the range 30,000-50,000 K. The visual spectrum shows Balmer lines and weak He II 4686 A lines. Balmer-line width and a fit of the UV-visual flux distribution using the Blackwell-Shallis (1977) algorithm yie…

1989 • The Astronomical Journal

IUE 1

Discovery of an X-Ray Selected Optically Highly Variable Quasar

DOI: 10.1007/BFb0031171 Bibcode: 1989LNP...334..261B

Tagliaferri, G.; Branduardi-Raymont, G.; Giommi, P. +5 more

In the course of a programme of optical identification of serendipitous EXOSAT sources we have discovered a quasar (EX0033041-2613.1, referred to here as Gepu; z = 0.67) which varied by more than 3 magnitudes between November 1985 and February 1988. We present the results of optical spectroscopy and CCD photometry of the quasar which were obtained…

1989 • BL Lac Objects

Exosat 1