Search Publications

Star-Forming Galaxies in the Infrared

Weedman, Daniel W.

The infrared properties from IRAS of galaxy samples previously observed in the optical and ultraviolet are summarized in order to predict quantitatively the infrared fluxes corresponding to galaxies of given fluxes in other wavebands. An infrared luminosity function of galaxies is presented and used to predict galaxy counts and redshift ranges at …

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…

EXOSAT Observations of the Hot Gas in the A1060 Cluster of Galaxies

Singh, K. P.; Westergaard, N. J.; Schnopper, H. W.

We have used the EXOSAT Observatory to map and to obtain the X-ray spectrum of the hot gas in the A1060 cluster of galaxies. The density and temperature profiles of the intracluster gas have been determined by spherical deprojection of the X-ray surface brightness distribution obtained. We assume hydrostatic equilibrium and a cluster gravitational…

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…

Analysis of IUE Data on V426 Ophiuchi: Outburst and Orbital Variability

Szkody, Paula; Mateo, Mario

Time-resolved IUE spectra throughout two orbits of the dwarf nova V426 Oph during quiescence are presented. It is found that the visual and C IV fluxes remain relatively constant during both orbits, whereas the UV coninua and Mg II lines vary by 20-30 percent. The time scales of this variability are discussed. Analysis of other spectra at brighter…

SN 1987A in the UV : the progenitor star, the reddening and the possible detection of a UV light echo.

Gilmozzi, Roberto

X-ray bursts - Some recent developments

Lewin, Walter H. G.; van Paradijs, Jan

In this paper we review recent developments in the areas of burst recurrence, and mass-radius relations of neutron stars. We reach the surprising conclusion that the time-averaged X-ray luminosity emitted in type 1 bursts is approximately independent of the persistent X-ray luminosity over a large range (factor of ~30) of the latter. We conclude t…

EXOSAT Observations of the Globular Cluster X-ray Sources X0512-401 and X1745-203

Ercan, E. N.; Branduardi-Raymont, G.; Kiziloglu, U.

The authors observed X0512-401 with the Exosat LE and ME and present here the results of the spectral analysis made of the data. The spectral model best fitting the combined LE and ME data is a single thermal Bremsstrahlung. A single blackbody model is excluded by these observations. A power-law is generally a worse representation of the data than…

Serendipitous discovery of an AGN showing rapid X-ray variability.

Barstow, M. A.; Stanger, V. J.

A serendipitous X-ray source, discovered by EXOSAT in the field of the hot, helium-rich degenerate star PG1159-035, has been identified with the 15.1-mag galaxy ZWG 013.024. The object is classified as Seyfert 1 and has a redshift of 0.019, implying a distance of 117 Mpc. ZWG 013.024 has an unusually soft medium-energy (0.5-6 keV) X-ray spectrum (…

Lyman: A new window on the universe - The phase A science report of the Australian Lyman Science Working Group

Cropper, M.; Tuohy, I. R.; Dopita, M. A. +2 more

The scientific objectives, technical feasibility, and engineering implementation of the Lyman high-orbit UV space observatory are discussed. The Lyman observatory is designed to study the waveband between 900 and 1250 A. The objectives of the mission include stellar research, the study of stellar evolution, planetary nebulae, the study of binaries…