Search Publications
EXOSAT observations of active galactic nuclei
McHardy, I.; Branduardi-Raymont, G.; Molteni, D. +3 more
EXOSAT observations of the Type 1 Seyfert galaxies NGC3783 and NGC5548 are reported. Contrary to previous findings, the X-ray spectrum of NGC3783 is not heavily cutoff at low energies. This suggest that the conditions of the broad-line region in NGC3783 are different from those in which the earlier data were obtained. We speculate on the presence …
X-ray emission from the planetary nebula NGC 1360
Jansen, F. A.; McKechnie, S. P.; de Korte, P. A. J. +1 more
The EXOSAT observatory has detected the nucleus of NGC 1360 in four photometric energy bands. The data rules out that the emission is from blackbody origin. Initial fits made with LTE model atmosphere spectra require the presence of highly ionized Oxygen and Neon in the stellar atmosphere.
The exosat mission
Taff, L. G.; Beatty, D. E.; Yakutis, A. J. +1 more
Exosat, the European X-ray Observatory, was placed in orbit on 26 May 1983. The spacecraft, stabilized axes in three to a few arc second, carries four instruments, two one-metre focal length imaging telescopes, a large area proportional counter array and a gas scintillation proportional counter spectrometer. The salient features of the instrumenta…
Spectral and temporal studies of various late-type stars
McHardy, I.; Mewe, R.; Brinkman, A. C. +2 more
The RS CVn stars Capella and σ2 CrB have been measured with EXOSAT in soft and medium X-rays for about 24 hours each and the less active late-type star Procyon for about 6.5 hours. In addition, the RS CVn star γ. And was twice observed about one month apart for a total of about 7 hours, with the ME and the LE in the photometer mode only…
Exosat observations of the galactic bulge X-ray source GX17+2
Sztajno, M.; Truemper, J.; Langmeier, A. +1 more
We have measured the X-ray flux of the bright galactic bulge source GX17+2 in the energy range 1-20 keV using the EXOSAT ME experiment. During 8 hours of continuous observation an X-ray flare was observed (lasting ~1 hr) followed by an intensity increase. The data show intensity dips with a quasiperiod of ~1.4 hours and quasi-periodic oscillations…
EXOSAT observations of the Perseus cluster
Fabian, A. C.; Branduardi-Raymont, G.; Manzo, G. +3 more
EXOSAT CMA and GSPC observations of the Perseus Cluster of galaxies are reported. The soft X-ray image data confirm the earlier Einstein Observatory results in terms of the density distribution radially outward from NGC1275. We have used the GSPC spectral data at higher energies to study the strength of the X-ray continuum and of the Fe line emiss…
X-ray observations of Vela-X
Smith, A.; Zimmermann, H. U.
Exosat ME observations of the Vela-X region are presented. It is found that the 2-10 keV emission is divided into two components. One is associated with the rulsar but is probably extended by 10-20 arc minutes, the other is associated with the Vela-X radio nebula and is probably more extended (≈ 1 degree). The Vela-X component is softer than the p…
Is cygnus X-3 a low-mass X-ray binary?
van der Klis, M.; Jansen, F.
We present examples of the quasi-periodic variations in the X-ray flux of Cyg X-3 which we have recently found during observations of this source with EXOSAT. Amplitudes and periods of the variations range from 5% to 20% of the total flux and from 50 to 1500 s, respectively. Our tentative interpretation of these quasi-periodicities, the occurrence…
Search for millisecond rotational periods in some low-mass X-ray binaries observed by EXOSAT
Sztajno, M.; Truemper, J.; Langmeier, A.
We present the results of a search for millisecond rotational pulsations in the X-ray emission of five low-mass X-ray binaries: MXB1728-34, 4U1702-42, 4U1705-44, 4U1755-33 and GX17+2. The data were obtained by the EXOSAT Medium Energy Experiment Argon Counters (1-20 keV) with a time resolution of 7.8125 milliseconds. We searched for periods in the…
Interpretation of the measurements of secondary electron currents induced by impacts during the flyby of comet Halley
Grün, E.; Grard, R.; Apáthy, I. +3 more
The Giotto, Vega-1 and Vega-2 spacecraft flew through the environment of comet Halley at a relatively close range with velocities of the order of 70-80 km/s. The fore sections of their surface were bombarded by neutral molecules and dust grains which caused the emission of secondary electrons and sputtered ions. This paper makes use of the seconda…