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IRAS and near-infrared observations of the Seyfert galaxies MCG 8-11-11, MKN 79 and MKN 279.
Roth, M.; Di Cocco, G.; Coe, M. J. +11 more
IRAS-pointed observations and near-infrared photometry of the Seyfert galaxies MCG 8-11-11, Mkn 79 and Mkn 279 are presented. Superimposed on a power law behaviour with α = -1.2, MCG 8-11-11 shows an excess at 25 µm which can be accounted for by black body emission at ≡200K from a dust emitting region of 73 pc or more. Mkn 79 has a single po…
Ultraviolet continuum variability of the quasar 3C273
Ulrich, M. H.; Courvoisier, T. J. -L.
Several quasars show an excess of radiation in the ultraviolet over the power law defined by their infrared/optical continuum. Several authors1-4 have fitted the infrared to ultraviolet spectrum of these quasars with a combination of a power law component, line emission, blends of Fe II lines, Balmer continuum and a black-body component…
The resonance lines of B II and Be II in Hg-Mn stars.
Sadakane, K.; Jugaku, J.; Takada-Hidai, M.
The resonance lines of B II and Be II are analyzed in 25 Hg-Mn stars. The B II line is present in nine (36 percent) stars, and the line is absent in the remaining stars. Strengths of the B II and Be II lines are in accordance with the predictions of the diffusion theory for about half the sample stars. Five Hg-Mn stars show the strong B II line an…
A space-borne plasma analyser for three-dimensional measurements of the velocity distribution
Coates, A. J.; Winningham, J. D.; Johnstone, A. D. +3 more
A new type of plasma analyzer, capable of covering the three-dimensional energy distribution of charged particles from a spinning spacecraft, has been built for the AMPTE and GIOTTO spacecraft. The novel features are the use of 260 deg of deflection in a spherical plate electrostatic analyzer to obtain energy discrimination simultaneously with dis…
Ultraviolet, optical and infrared observations of the intermediate polar TV Columbae.
Szkody, P.; Mateo, M.; Hutchings, J.
Forty-three IUE spectra of the X-ray discovered, triply periodic cataclysmic variable, TV Col are examined. The results show that the UV flux varies with the four-day period discovered by Motch in 1981. By fitting continuum models to the UV and optical fluxes, it is inferred that this modulation corresponds to the periodic heating of a normally 90…
Variations in the variability of RR Tel.
Manfroid, J.; Heck, A.
The visible-light periodicity of the very slow nova RR Tel is inferred to vary in cycles of 350- to 410-day periods, based on the uvby photometric data, IUE FES measurements, and AAVSO visual estimates. Besides a general increase in magnitude, the visible lightcurve is also marked by two events corresponding to sudden decreases of brightness in 19…
Study of Rapid Variability in CYGNUS-X-1
Page, C. G.
The EXOSAT Medium Energy instrument has been used with the new HER6 mode to study the rapid variability of Cygnus X-1. It was found that the fluctuations in the higher energy band (5 - 14 keV) lagged behind those in the lower band (2 - 5 keV) by about 6 milliseconds. This confirms predictions of the inverse Compton model and gives an upper limit t…
IUE observations of the Seyfert 1.9 galaxy Markarian 423.
Rudy, R. J.; Puetter, R. C.; Cohen, R. D.
UV observations of the Seyfert 1.9 galaxy Markarian 423 show a moderately strong UV continuum in the 1200-2000 A region, a strong narrow Lyman-alpha conponent, and no detectable broad lines. This absence of broad UV lines, in conjunction with the steep broad line Balmer decrement, indicates that the gas giving rise to the broad emission lines is s…
Observation of an X-Ray Outburst and Quiescent Emission from the Rs-Canum Binary HR1099
Barstow, M. A.
The RS CVn binary HR1099 has been observed with the medium energy (ME) and low energy (LE) experiments on EXOSAT. X-ray emission was detected from two quiescent components with temperatures ∼4.5 × 105K and ∼4 × 107K, which were observed to flare during the observation. The data are compared with models of coronal behaviour. A…
Upper limits to coronal line emission from X-ray detected T Tauri stars.
Penston, M. V.; Johnstone, R. M.; Lago, M. T. V. T.
High dispersion AAT spectrograms of the two T Tauri stars, GW Orionis and T Tauri, are used to set upper limits to the intensities of the coronal emission forbidden line of Fe XIV at 5303 A. Comparison made with the intensities of chromospheric and the transition-region emission lines, and of the X-ray flux, shows that in GW Ori the Fe XIV forbidd…