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Tomographic Separation of Composite Spectra. I. The Components of Plaskett's Star
Wiggs, Michael S.; Gies, Douglas R.; Bagnuolo, William G., Jr.
The UV photospheric lines of Plaskett's Star (HD 47129), a 14.4 day period, double lined O-type spectroscopic binary were analyzed. Archival data from IUE (17 spectra well distributed in orbital phase) were analyzed with several techniques. A cross correlation analysis, which showed that the secondary produces significant lines in the UV, indicate…
Ulysses at Jupiter: An Overview of the Encounter
Smith, E. J.; Wenzel, K. -P.; Page, D. E.
In February 1992, the Ulysses spacecraft flew through the giant magnetosphere of Jupiter. The primary objective of the encounter was to use the gravity field of Jupiter to redirect the spacecraft to the sun's polar regions, which will now be traversed in 1994 and 1995. However, the Ulysses scientific investigations were well suited to observations…
Preliminary Analysis of an Ultraviolet Hubble Space Telescope Faint Object Camera Image of the Center of M31
Boksenberg, A.; Barbieri, C.; Weigelt, G. +17 more
A 5161 s exposure was taken with the FOC on the central 44" of M31, through a filter centered at 1750 A. Much of the light is redleak from visible wavelengths, but nearly half of it is genuine UV. The image shows the same central peak found earlier by Stratoscope, with a somewhat steeper dropoff outside that peak. More than 100 individual objects …
X-Ray Luminosity and Spectral Variability of Hard X-Ray--selected Active Galactic Nuclei
Tagliaferri, G.; Giommi, P.; Grandi, P. +2 more
One hundred sixty-one observations archived in the EXOSAT data base are analyzed in order to study time and spectral variability of all 30 sion-line active galactic nuclei (AGNs) in the Piccinotti sample. For each source long-term (from days to months) and short-term (from minutes to hours) luminosity variations were sought using the soft (LE: 0.0…
The EXOSAT obseravtions of SS Cygni.
Watson, M. G.; Jones, M. H.
A series of nine observations of SS Cygni made using Exosat between 1983 November and 1984 September are presented. Distinct soft amd hard X-ray emitting components were spectrally resolved by the LE and ME instruments, respectively. In quiescence the source shows hard X-ray emission with a 2-10 keV luminosity of 1.2 x 10 exp 33 (d/200 pc)-squared…
The HIPPARCOS Input Catalogue. I - Star selection
Arenou, F.; Crifo, F.; Gomez, A. +7 more
The Hipparcos Input Catalogue has been compiled, over the period 1982-1991, as the definitive observing catalog for the ESA's Hipparcos satellite, launched on 8 August 1989. It contains the most up-to-date, comprehensive, and homogeneous information on the 118,000 stars being observed by Hipparcos. Its stellar and data content is described in a se…
Hubble Space Telescope Imaging of the North Polar Aurora on Jupiter
Caldwell, J.; Hua, X. -M.; Turgeon, B.
The first direct images of the Jovian aurora at ultraviolet wavelengths were obtained by the Hubble Space Telescope Faint Object Camera near the time of the Ulysses spacecraft encounter with Jupiter on 8 February 1992. The auroral oval is not uniformly luminous. It exhibits a brightness minimum in the vicinity of longitude 180^circ. In the few ima…
GINGA and EXOSAT observations of the Perseus cluster of galaxies.
Fabian, A. C.; Allen, S. W.; Edge, A. C. +2 more
We report observations of the Perseus cluster of galaxies made using the Ginga and EXOSAT satellites. Our results from Ginga indicate that the region around the centrally dominant galaxy NGC 1275 is well described by a model incorporating emission from an isothermal, diffuse plasma of temperature ~6.3 keV, metal abundance ~ 0.4 solar, a cooling fl…
Models for the remnants of recurrent novae - III. Comparison with the X-ray observations of RS Ophiuchi (1985).
Bode, M. F.; O'Brien, T. J.; Kahn, F. D.
The X-ray emission predicted by a model for the interaction of ejecta with a circumstellar medium is compared to Exosat observations of the 1985 outburst of the recurrent nova RS Ophiuchi. The model parameters are constrained by fitting the predicted spectrum to the first X-ray observation, made 55 days after the outburst, and are found to be cons…
The NDAC HIPPARCOS data analysis consortium - Overview of the reduction methods
Snijders, M. A. J.; Evans, D. W.; Lindegren, L. +7 more
This paper gives an overview of the assumptions and algorithms adopted by the Northern Data Analysis Consortium (NDAC) for the reduction of data from the space astrometry satellite Hipparcos. A fairly detailed account is given of the main steps of the reduction, viz., the attitude determination, analysis of image dissector tube data, great-circle …