Search Publications
Inflow of halo gas from the direction of the galactic North Pole.
Savage, B. D.; de Boer, K. S.
A far-UV echelle spectrum has been obtained of the UV-bright star vZ1128 in the globular cluster M3. This cluster lies in a direction 11° off the galactic North Pole at a distance of about 10 kpc. Only the usually strong interstellar lines are recognizable in the faint spectrum, and they show absorption at velocities from near +40 km s-1
The ultraviolet (IUE) spectra of the lambda Bootis stars.
Heck, A.; Jaschek, M.; Jaschek, C. +4 more
Ultraviolet spectra of several λ Boo stars and λ Boo candidates have been obtained with the IUE satellite in low- and in high-resolution. It is possible to discriminate the λ Boo stars from the normal A stars on low resolution spectra by their strong absorption features at λλ1600, 1657(C I), 1931(C I), and 3040 Å. The λ1600 feature, about 80 Å wid…
Variable blue supergiants in the Large Magellanic cloud : R 84, R 85 and R 99.
Stahl, O.; Leitherer, C.; Zickgraf, F. -J. +3 more
During a search for luminous blue variables in the LMC the three emission-line stars R 84 (OIafpe), R 85 (B5Iae), and R 99 (OBf:pe) have been found to show significant brightness and colour variations. Photometric and spectroscopic data from the UV to the IR have been used to discuss the nature of these variables. It is argued that they are closel…
The orbital parameters and the X-ray pulsation of VELA X-1 (4U 0900-40).
van der Klis, M.; Bonnet-Bidaud, J. M.
Results are presented of an analysis of 83 d of 2 - 12 keV X-ray observations of Vela X-1 (4U 0900-40) obtained with the ESA COS-B satellite. Combining the present determinations of the orbital epoch from pulse timing with those obtained with other satellites, the data are found to be consistent with an increase of the orbital period at a rate (P/…
Bolometric corrections for peculiar B-type stars.
Lanz, T.
Semi-empirical bolometric corrections are estimated for 25 peculiar stars and 13 comparison stars from IUE low dispersion spectrum and from theoretical fluxes best fitting the Geneva colour indices. When corrected for reddening, the relation BC vs. (B2-G)0 for main-sequence stars matches fairly well the theoretical relation computed by …
Nebular and interstellar absorption lines in planetary nebulae : the case of NGC 6543.
Pottasch, S. R.; Pwa, T. H.; Mo, J. E.
Using high resolution IUE spectra it is possible to separate the narrow absorption lines due to the interstellar material and the nebular matter. The analysis of nebular absorption lines has three advantages. First the column densities of ions different from those observed in emission can be determined. The abundance of the elements are then readi…
The 1200-3200 A spectra of Seyfert I galaxies : MK 304, NGC 7603, MCG8-11-11, ESO 12-G 21 and NGC 1566.
Clavel, J.; Joly, M.
The 5 Seyfert I galaxies MK 304, NGC 7603, MCG 8-11-11, ESO 12-G 21, and NGC 1566 have been observed with IUE (1200 - 3200 Å). Their UV spectrum is rich in emission lines. A steep rise of the continuum toward shorter wavelengths is observed below ≡2000 Å in 4 of these objects; this excess is interpreted as thermal emission from an accretion disk. …
Quantification of the order overlap problem for IUE high resolution spectra (SWP camera). A correction algorithm.
Bianchi, L.; Bohlin, R. C.
A quantification of the order overlap in IUE high resolution spectra is obtained, for the SWP camera, by comparison of line depths measured in IUE and Copernicus spectra. The amount of order overlap is found to be about 32 percent of the net spectrum at 1150 A, decreasing to zero at about 1400 A, for data extracted with the most recent production …
An upper limit to the abundance of 9Be in the population II star HD 76932 from a high resolution spectrum with the IUE.
Molaro, P.; Beckman, J.
A high resolution spectrum (Δλ = 0.2 Å) of the Population II star HD 76932 from the archive of the IUE satellite has been analysed in a search for measurable resonance absorption lines due to 9Be. Matching the observations by a synthesized model of the wavelength region around the doublet at 3130 Å gives a conservative upper limit for t…
Non-LTE analysis of subluminous O-stars. VI. Feige 110.
Heber, U.; Kudritzki, R. P.; Hamann, W. -R. +3 more
An analysis of the ultraviolet (1150-2000 A) and the blue 4000-5100 A) spectra of the subdwarf O-star Feige 110 is presented. Effective temperature, gravity and helium abundance of Feige 110 are determined on the basis of NLTE model atmospheres. The effective temperature of Feige 110 is found to be 40,000 K (+5000 or -3000 K). Helium abundances in…