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Observations of Comet Crommelin. IV - Upper limit on the optical depth in the coma at ultraviolet wavelengths
Evans, A.; Zarnecki, J. C.; Bode, M. F. +2 more
The bright (V = 9.1) star SAO 152362 was observed with the long-wavelength (LWP) camera of the IUE satellite before and during a close approach by Comet Crommelin. No significant change in the ultraviolet spectrum of the star occurred during the encounter and an upper limit is set on the optical depth of the dust in the coma of the comet.
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…
An EXOSAT Observation of the Morphology of the Coronal X-Ray Emission from Algol
Parmar, A. N.; White, N. E.; Culhane, J. L. +4 more
The X-ray emission from Algol is thought to originate in a corona associated with the K star in this system. We report the results of a 35 hr continuous EXOSAT observation through secondary optical eclipse that was designed to measure the structure of the corona. No obvious X-ray eclipse was seen. The spectrum measured by the ME gives a temperatur…
Exosat observations of the supernova remnant cas a
Branduardi-Raymont, G.; Manzo, G.; Jansen, F. A. +6 more
The young supernova remnant Cas A has been observed with the imaging proportional counter (PSD) of the EXOSAT observatory. High quality spatially resolved, spectral data allow for the first time the determination of the temperature structure of the remnant. Preliminary results on the distribution of temperature and emission measureover the remnant…
A simultaneous X-ray and radio observation of a flare from Algol
Parmar, A. N.; White, N. E.; Culhane, J. L. +1 more
An X-ray flare was observed from Algol using the low and medium energy detectors on the European Space Agency's EXOSAT observatory. Spectra obtained during the flare are well fitted by thermal continua while an Fe XXV emission feature was also detected. The strength of this feature indicates a cosmic abundance for iron. The data indicate that the …
Optical Observations of Serendipitous EXOSAT Sources in the Coma Cluster
Branduardi-Raymont, G.; Mason, K. O.; Martin, C. +2 more
A ∼7 hour observation of the central part of the Coma Cluster of galaxies has been performed with the EXOSAT LE telescopes and CMA detectors. Five serendipitous sources are detected within the inner 35 arcmin radius of the field. Optical spectroscopy demonstrates that at least three of these are background AGN not associated with the cl…
The Discovery of Low-Level Iron Line Emission from CYGNUS-X-1
White, N. E.; Barr, P.; Page, C.
We present the results of seven observations of the X-ray spectrum of Cyg X-1, made with the GSPC on board the EXOSAT observatory. We report the discovery of an iron emission line in its spectrum. The likely origin of this feature is discussed.
The Spectral and Temporal Variability of the X-Ray Transient 4U1630-47
Stella, L.; Parmar, A. N.; White, N. E.
We present the results of four observations made by the European Space Agency's EXOSAT Observatory of the X-ray transient 4U1630-47 during its 1984 outburst. We observed marked spectral changes as the source decayed from a maximum observed intensity of 8×10-9 erg/cm2/sec (1.5 10 keV). The spectrum could be modelled by a soft …
2 10 KeV spectra of Crab-like SNR's as observed by EXOSAT
Smith, A.; Davelaar, J.
The EXOSAT ME observations of 3C58 and G21.5-0.9 are presented. The data for these objects is considered in conjunction with the data available from EXOSAT for the Crab-like SNR's Crab and Vela X. The objects have single power law spectra with a range of spectral indices of 0.6 to 1.5, 3C58 and Vela X being similar to the Crab whilst G21.5-0.9 and…
Some crucial X-ray observations — One or two SNR(s) in Crux?
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +2 more
A new EXOSAT (LE/CMA) observation of the region in Crux (R.A. ∼11h 45m, Dec. ∼-62°) where Markert et al. (1981) reported the existence of two x-ray SNR's is presented. After “cleaning” the CMA field from the point source component, due to the UV emission of the numerous stars in the field, the smoothed x-ray contours are compared to the 408 MHz ra…