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Markarian 52 : a gas-rich starburst galaxy.

Durret, F.; Tarrab, I.

We have observed the "starburst" galaxy Markarian 52(= NGC 4385) both through broad and narrow band imaging, and spectroscopically in the UV and optical ranges. The narrow band Hα+[N II] continuum-free image shows that the ionized gas extends over at least 19" (4.1 kpc). However, our long slit spectroscopic data reveals a much larger extent of the…

Line variations in the ultra-violet spectrum of the Ap-Si star HD 25823.

Artru, M. -C.; Freire-Ferrero, R.

Spectral variations of the Ap-Si star HD 25823 are investigated in the UV range 1250-1900 A, from a set of five IUE images recorded during one rotational period. It is found that line intensities, as well as other wide absorption features, vary versus the phase (up to 20 percent) with different behaviors related to the absorbing elements. The equi…

An active hemisphere on II Peg.

Doyle, J. G.

IUE observations of the RS CVn star II Peg in the upper chromospheric and transition regions lines Mg II k, C IV, and He II in 1981, 1983 and 1985 shows evidence for increased activity at certain phases. The Mg II k line flux shows an above average value between phases 0.0 and 0.5. This is largely biased by the 1981 and 1983 data-sets, although th…

EXOSAT observations of the southern cluster of galaxies S 2008-569.

Piro, L.; Fusco-Femiano, R.

We present the X-ray spectrum of the source 3A 2008-568, associated with the southern cluster of galaxies S 2008-569, obtained with the ME detectors aboard the EXOSAT satellite. The flux was detected in a quadrant pointing in offset position to monitor the background during an observation of another target. An average intracluster gas temperature …

Scattered light between 2 and 13 arcmin from dzeta Orionis in the 1200 to 3000 A wavelength range.

de Boer, K. S.; Kuss, C.

The nature of the spatial enhancement in the scattered intensity in the satellite UV near ζ Ori is investigated. After correction for the scattering contributed by the IUE telescope, the normalised dust-scattered intensity near ζ Ori indicates the presence of small patches of dust very close to ζ Ori inside the larger diffuse shell of Barnard's Lo…

Discrete absorption components : a study of the gas parcel model using component velocity observations.

Bates, B.; Catney, M. G.; Halliwell, D. R.

Available IUE spectra for Beta Ori are used to test the model (Underhill and Fahey, 1984) of the release of discrete parcels of gas from above the stellar photosphere as a possible origin for the discrete absorption components noted in UV spectra. The applicability of late-B supergiants to the present parcel model is questioned. It is suggested th…

The circumstellar environment of the Herbig Ae/Be stars. The case of AB Aurigae.

Fonti, S.; Blanco, A.; Strafella, F.

The possibility that the near-infrared excess observed for AB Aur is due to free-free emission coming from a circumstellar H I region is investigated. The analysis of absorption lines (mainly of Fe II) present in IUE spectra shows that both the derived column densities and the excitation temperature (about 2000 K) indicate the presence of a conspi…

Erratum - a 23H EXOSAT Observation of the X-Ray Pulsar 1E:2259+586 and the Associated Supernova Remnant G:109.1-1.0

Coe, M. J.; Dennerl, K.; Hanson, C. G. +1 more

SC 2059-247 : no evidence for cluster evolution or extreme X-ray properties.

Kaastra, J. S.; de Korte, P. A. J.

The southern cluster SC 2059-247 has been observed by the X-ray satellite EXOSAT. The cluster has a high luminosity and cooling mass flow and a small core radius, but it has neither exceptional properties compared to other clusters, nor does it show signs of evolution effects, as was concluded from earlier Einstein observations.

Detection of energetic electron (E greater than KeV) and ion fluxes (E greater than 97 KeV) from comet P/Halley by the Giotto experiment EPA on 1986 March 13/14

Neubauer, F. M.; Kirsch, E.; O'Sullivan, D. +2 more

Relativistic electron fluxes (greater than 220, greater than 300 KeV) were recorded during the Giotto encounter with comet P/Halley from the inbound to the outbound bowshock. A strong enhancement in the greater than 300 KeV electron flux was measured about 1 hr after the outbound crossing of the bow shock. It is suggested that the electrons were s…