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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…
The ultraviolet variability of early-type supergiants.
Underhill, A. B.
Four early-type supergiants - HD 79186 (B5 Ia), HD 96919 (B9 Ia), HD 105056 (ON9.7 Iae), and HD 148379 (B2 Iae) - have been observed with the low-resolution spectrographs of IUE in the large aperture on 14 days. The behavior of the ultraviolet fluxes with time is studied. The light from all four stars seems to vary. Typically the dispersion about …
Search for discrete gamma-ray sources emitting at energies greater than 10(exp15) eV.
Samorski, M.; Stamm, W.
The data of the extensive air shower experiment at Kiel have been scanned systematically for possible discrete γ-ray sources in the energy range E > 1015 eV and in the declination band δ = 25° - 75°. Photon fluxes for celestial positions with the statistically most significant excesses of showers and 3 σ upper limit photon fluxes for…
The IUE spectrum of gamma 1 Velorum.
Sahade, J.; Hernandez, C. A.
Gamma(1) Vel is suggested by IUE observations to be an interacting binary system with nonthermal energy sources and the possibility of two high electron temperature regions, as well as mass outflow from one of the components. A UV continuum is obtained which fits the Kurucz (1979) LTE model atmosphere computations for an effective temperature of 2…
New observations of the CIV and N V resonance doublets in the planetary nebula NGC 3918.
Pena, M.; Torres-Peimbert, S.
We present new short wavelength high dispersion lUE measurements of the resonance doublets 1238/1243 of N V and 1548/1551 of C IV. The observed intensity ratios are of 1.87±0.15 for N V and 1.83±0.11 for C IV; compatible, within the observational uncertainties with the expected ratio of 2.
A search for chromospheric emission in TU Cassiopeiae spectra.
Henden, A. A.; Cornett, R. H.; Schmidt, E. G.
The authors have searched high-resolution spectra of the multimode cepheid TU Cas for evidence of chromospheric emission. Spectral regions covered include the Ca II near-IR triplet near 8600 Å, Hα, Ca II H and K, Mg II h and k; phase coverage in both primary and secondary modes was reasonably complete. There was no evidence for changes other than …