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The first IUE observations of LMC X-1 (star 32).
Pakull, M.; Bianchi, L.
The first far UV observations of LMC X-1 (star 32) are presented. Form the UV continuum distribution the authors derive a value for the reddening towards star 32 of E(B-V) = 0.05 (galactic foreground extinction) plus 0.32 (extinction in the LMC). The dereddened stellar continuum can be reproduced by a model atmosphere with Teff = 35,000…
Alpha Trianguli Australis (K2 II-III) : hybrid or composite ?
Ayres, T. R.
The prototype "hybrid-spectrum" giant, α Trianguli Australis, exhibits a far-ultraviolet continuum which is considerably bluer than would be expected of a star of its optical colors, suggesting the presence of a previously unrecognized companion. If the K type primary is as luminous as indicated by the widths of its Ca II and Hα lines, the compani…
The Big Dipper - 4U1624-49
Halpern, J.; Grindlay, J. E.; King, A. R. +2 more
We present a 6.3 hour observation of 4U1624-49 with the EXOSAT Medium Energy experiment. The X-ray light curve is dominated by a series of sharp dips in which the observed flux falls to ∼25% of the steady level on timescales of seconds. These dips are accompanied by strong variations in the spectral hardness consistent with large changes in the ab…
X-Ray Emission from Isolated Hot White Dwarfs
Heise, J.
Hot white dwarfs are objects that copiously emit in the Extreme Ultraviolet and soft X-ray range. They are the brightest sources seen in the Low Energy Telescope of EXOSAT, with countrates up to 25 cnts/s. in contrast to their optical and UV spectrum the total flux and spectral distribution at soft X-ray energies are highly sensitive to the effect…
PHL 227 : the discovery of a new nova-like object.
Heber, U.; Koester, D.; Hunger, K.
The southern (13.5-mag) subdwarf candidate PHL 227 is found to be a nova-like object (UX UMa star). The line spectrum, both at visual and UV wavelengths, is strikingly similar to that of the well known UX UMa star V3885 Sgr. PHL 227 lies in the sky region of the Palomar Green survey. In this survey only two UX UMa stars (brighter than B = 16.2) so…
EXOSAT observations of the X-ray pulsar 4U1145-619
Warwick, R. S.; Watson, M. G.; Willingale, R.
EXOSAT observations of the X-ray pulsar 4U1145-619 during June and July 1983 and July 1984 confirm that this source shows a regular 187 day outburst cycle in X-rays. The results from pulse timing and X-ray spectroscopy are discussed in terms of a model for 4U1145-619 involving an eccentric binary system in which there is variable accretion from th…
EXOSAT and Optical Observations of the X-Ray Burst Source 4U/MXB1636-53
Pietsch, W.; van Paradijs, J.; van der Klis, M. +5 more
During May 1984 we made a one-day EXOSAT observation of the X-ray burst source 4U/MXB1636-53, partly simultaneous with Tenma and with optical observations at ESO. In this paper we give a short description of the main results: (i) Discovery of a constant blackbody component in the persistent X-ray emission, with an apparent blackbody radius consist…
Infrared photometry of Seyfert 1.8 and 1.9 galaxies.
Rudy, R. J.; Rodriguez-Espinosa, J. M.
Infrared photometry is reported from 1.25 to 10 micrometers for 10 Seyfert 1.8 and 1.9 galaxies identified by Osterbrock and his collaborators and drawn originally from the Markarian lists. The three objects whose infrared colors are the most nonstellar in nature are objects whose ultraviolet or optical spectra preclude heavy reddening of either t…
H-alpha variability in X-ray transient source X0331+53.
Iye, M.; Kodaira, K.
Spectroscopic observations of X0331+53 between October 1984 and March 1985 revealed that the equivalent width of Hα emission decreased by a factor of about four relative to that observed one year ago. This finding, in association with the decline of X-ray activity of the source reported by the EXOSAT group, is interpreted to support the binary mod…
The Bright Pre-main Sequence Variable HR5999
Talavera, A.; Mewe, R.; Catala, C. +7 more
A meeting to review the reduced coordinated observations by EXOSAT, IUE and ground-based instruments of the bright and variable Herbig A7e star HR 5999 is summarized. The attempt was to delineate the relationship between the various observable quantities of its atmosphere (colors, emission-line fluxes, wind velocities, etc.) in order to develop a …