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The structure of Herbig-Haro object 43 and Orion dark cloud extinction.
Cohen, M.; Dopita, M. A.; Schwartz, R. D.
New ultraviolet and optical observations of Herbig-Haro object No. 43 are reported. Continuum and emission-line fluxes in the wavelength range 1250 to 7350 A have been measured. The continuum fluxes are best matched by an enhanced H exp 0 two-photon component added to H free-bound emission, assuming a Theta Ori extinction curve with E(B - V) = 0.2…
Observations of the low-redshift broad absorption line QSO PG 1700+518 : limits on the fraction of QSOs with broad absorption lines at low redshift and the physical conditions in the broad absorption line region.
Peterson, B. M.; McMahon, R. G.; Weymann, R. J. +3 more
The authors present IUE and optical observations demonstrating that the zem = 0.29 QSO PG 1700+518 is a broad absorption line (BAL) QSO. This object is unique because of its low redshift and because it is one of only two BAL QSOs which exhibit moderate strength Mg II BALs. The discovery suggests that the fraction of QSOs with BALs at lo…
Models for the planetary nebulae NGC 4361 and NGC 1535 : influence ofthe stellar wind on the nebular ionization.
Koeppen, J.; Adam, J.
Model atmospheres fitted to line profiles of the central stars (Méndez et al., 1981) are used to construct nebular ionization models for the planetary nebulae NGC 4361 and 1535. For NGC 4361 the optical and IUE nebular emission lines are reproduced satisfactorily well. For NGC 1535 the model atmospheres only emit less than 10-3 of the n…
The old nova V603 AQL : an intermediate polar ?
Haefner, R.; Metz, K.
A total of 1510 UVB photometric observations obtained with the 50-cm telescope at ESO in 13 6-h runs during July-August 1981 and two-channel polarimeter measurements obtained at the 60-cm Bochum and 1-m telescopes at ESO during the same period are reported for the old nova V 603 Aql. The data are presented in graphs and tables and characterized in…
PG 1700+518 : a low-redshift, broad absorption line QSO.
Boksenberg, A.; Pettini, M.
The first high-resolution optical spectra and lower resolution UV spectra of PG 1700 + 518, the only known broad-absorption-line (BAL) QSO at low emission redshift (0.288) are presented. The optical data were obtained with the Isaac Newton Telescope on the island of La Palma and the UV data with the International Ultraviolet Explorer satellite. Th…
Ultraviolet spectral morphology of the O stars. III. The ON and OC stars.
Walborn, N. R.; Panek, R. J.
Key regions in the 1200-1900-A spectra of two ON dwarfs and four ON/OC supergiants are illustrated and discussed, using high-resolution data from the International Ultraviolet Explorer archives. Marked anomalies are displayed by both stellar wind and photospheric C and N features, relative to the consistent framework provided by normal ultraviolet…
The interstellar radiation field and the production of inverse-Compton gamma rays in the Galaxy
Bloemen, J. B. G. M.
An empirical model for the large-scale galactic distribution of the various components of the interstellar radiation field is constructed using recent observations, and the spectral and spatial distribution of inverse Compton (IC) gamma ray production in the Galaxy is determined using the most recent estimate of the interstellar electron spectrum …
The MG II emission in W UMa-type binaries.
Rucinski, S. M.
Low-resolution IUE spectra of the Mg II emission line in eight contact binaries are presented. They are discussed together with the available observations in both resolution modes for other binaries, 15 systems altogether. The relative flux R(Mg II) = f(Mg II)/f(bol), which is known to be independent of the orbital phase, is used as a measure of c…
The X-ray spectrum of the supernova remnant W 49B from EXOSAT.
Jones, L. R.; Smith, A.; Pye, J. P. +1 more
X-ray observations of the supernova remnant W49B made by the medium-energy detector and gas scintillation propotional counter experiments on board Exosat are presented. The detection of a very strong emission line feature at 6.7 keV indicates a thermal origin of the X-rays. Fitting the spectral data with an optically thin thermal plasma model indi…
35-DAY Cycle and the Rotation Period of HERCULES-X-1
Pietsch, W.; Kahabka, P.; Truemper, J. +2 more
Sampling observations of a complete 35d cycle of Her X-1 during 1 March to 5 April 1984 with the low and medium energy X-ray detectors of EXOSAT are presented. The intensities measured in the Argon detectors are compared with the UHURU 35d light curve to obtain the turn-on times of two consecutive cycles as JD 2445753.0 ± 1.0…