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IUE detector saturation and the new 2800 Å absorption featre `discovered' by Karim, Hoyle, and Wickramasinghe
Savage, B. D.; Sitko, M. L.
The broad λ2800 Å absorption feature 'discovered' by Karim, Hoyle, and Wickramasingle is instrumental in origin. The feature is produced by IUE detector saturation effects in overexposed spectra.
The variable component of the NGC 4151 IUE spectrum : evidence foran expanding spherical emission shell.
Stoner, R.; Ptak, R.; Gregory, S.
The profile of the forbidden line of C III (1909) is the same in two pseudo-trailed, low-resolution SWP spectra of the nucleus of the Seyfert galaxy NGC 4151 obtained with the IUE in November 1980 and December 1982, respectively. In the 1980 spectrum, the C III forbidden line profile is also very nearly the same as that of the resonance line C IV …
Gamma rays from accreting matter onto collapsed objects
Giovannelli, F.; Karakula, S.; Tkaczyk, W.
In the spherical accretion onto massive objects, the matter may be heated up to temperatures as high as 1012 °K. In such a hot plasma, the thermal bremsstrahlung (e-e and e-p) and π° decay from inelastic collisions of protons are the main γ-ray sources. We determined the γ -ray production spectra from the π° decay and from bremsstrahlun…
Studies of high-latitude gamma rays
Strong, A. W.
COS-B gamma-ray data (70-5000 MeV) in the latitude range 10°< b <90° are compared with the expected emission from cosmic-ray interactions with interstellar gas. An additional component is found to be necessary to explain the latitude dependence of the emission. Two possible origins for this component are discussed: a gamma-ray halo around th…
Notes on the system TV Geminorum.
Underhill, A. B.
Low-resolution SWP spectra and high-resolution LWR spectra of the SRc variable star TV Gem have been studied. The available ultraviolet spectrophotometry and UBV photometry of the system can be interpreted in terms of the blended light from a B3.5 IV star and an M1 Iab star. The separation of the two stars is less than about 3 arc sec. Since the m…
P Cygni and related profiles in the ultraviolet spectra of O-stars.
Stalio, R.; Costero, R.
P Cygni and related profiles of the resonance lines of N V, Si IV and C IV ions are studied over a sample of 40 O-stars observed with IUE in the high resolution mode. The sample includes subdwarf stars, high luminosity population II objects, stars which are not recognized members of open clusters and/or associations, and stars which are members. T…
The broad band energy distribution of UV-bright BL Lac objects
Maraschi, L.; Tanzi, E. G.; Treves, A.
Renewed attention was paid to the study of the continuous energy distribution of BL Lac objects, bearing on the emission mechanisms of the central source, since the launch of the International Ultraviolet Explorer (IUE). The far ultraviolet domain (1000 - 3000 Å) is in fact particularly relevant to the problem, because it does not suffer from cont…
An analysis by wavelength coincidence statistics of the ultraviolet spectrum of kappa Cancri.
Bord, D. J.; Cowley, C. R.; Chjonacki, G. T.
Wavelength coincidence statistics (WCS) are used in conjunction with laboratory line intensity data and IUE data to study spectra of the Hg-Mn rich star K Cnc. The IUE data included the Fe II, Fe III, Mn II and Mn III lines. Attention was focused on the relative abundances as determined by matching the WCS line intensity spectra generated from lab…
The reflection nebula NGC 1999.
Cardelli, J. A.; Bohm, K. H.
The properties of dust particles in regions of recent star formation often seem to be different from the 'average galactic' dust properties. The present investigation is concerned with a determination of the ratio of nebular intensity to the stellar flux for the system NGC 1999/V380 Ori in the ultraviolet. It is found that the stellar flux curve i…
Interstellar CO in the direction of the runaway star AE Aurigae.
Nandy, K.; McLachlan, A.
The detection of absorption by interstellar (C-12)(O-16) in a high-dispersion IUE spectrum of AE Aur is reported. Relative to an estimated total hydrogen column density of about 21.62 in the line-of-sight, the measured CO column density of 14.76 + or - 0.10, is consistent with the theoretical model of Federman et al. (1980) for gas-phase chemistry…