Search Publications
High-Dispersion Observations of Alpha Bootis (K1 III) with the International Ultraviolet Explorer
Jordan, C.; Linsky, J. L.; Brown, A. +2 more
The authors have obtained very deeply exposed IUE echelle spectrograms of the bright, early-K giant Arcturus. They did not detect significant flux in the most prominent high-excitation species of a solar-like transition zone, C IV λ1548.2. The presence of a weak feature of Si III] λ1892.0, and possibly also Si IV λ1393.8, indicates the existence o…
On the Ultraviolet Spectra of Type I Supernovae
Branch, D.; Venkatakrishna, K. L.
A synthetic-spectrum technique, applied previously to the interpretation of the optical spectra of Type I supernovae, has been extended to the maximum-light near-ultraviolet spectrum. Spectral features in the interval 2750-3450 A are suggested to be complex blends of overlapping P Cygni profiles produced by numerous Fe II and Co II lines. This int…
Variability of the BL Lacertae Objects PKS 2155-304 and OJ 287 in the Far-Ultraviolet
Maraschi, L.; Tanzi, E. G.; Tagliaferri, G. +1 more
All the ultraviolet spectra of the two bright BL Lacertae objects PKS 2155 - 304 and OJ 287 taken with the International Ultraviolet Explorer in the period 1978-1984 are examined. For each spectrum the best-fitting power law is determined and a correlation between spectral slope and intensity is searched for. The correlation, if present, is weak. …
IUE Observations of Interstellar Hydrogen and Deuterium toward Alpha Centauri B
Moos, H. W.; Murthy, J.; Linsky, J. L. +3 more
A high dispersion profile is presented of the Lyman-alpha emission toward Alpha Cen B as recorded in two images taken with the IUE spacecraft. The spectra were examined with a three-parameter Gaussian or five-parameter solar-type profile to derive the intrinsic background stellar emission. Voight absorption profiles were calculated for the interve…
The High-Resolution Soft X-Ray Spectrum of HZ 43
Heise, J.; Bleeker, J. A. M.; Brinkman, A. C. +2 more
The authors present the high-resolution soft X-ray spectrum in the range 50 - 350 Å of the hot DA white dwarf HZ 43, obtained with the 500 lines mm-1 grating spectrometer on EXOSAT. Most remarkably, the spectrum indicates that the photosphere of HZ 43 consists solely of hydrogen, to a high degree of purity. Using a grid of hot, high-gra…
Z Camelopardalis: Outburst P Cygni Profiles and Quiescent Continuum
Szkody, P.; Mateo, M.
The authors present the first orbital study of the C IV P Cygni profile in the dwarf nova Z Cam, a system of intermediate inclination. A modulation of the absorption equivalent width is apparent, with phases suggesting an effect from the mass-transfer stream. Over the outburst cycle, the strength of the P Cygni absorption and emission components i…
IUE Observations of V Sagittae
Corcoran, M. F.; Koch, R. H.; McCluskey, G. E., Jr. +1 more
Observations of the nova-like variable V Sge are discussed, and the ground-based light curve is analyzed, compensating for the component interaction effect. Low-dispersion IUE spectra indicate that interstellar reddening is smaller than suggested from visible-band observations. The UV and visible continuum are modeled by a He-rich model and by a s…
Observations of Three BL Lacertae Objects: Constraints on Inhomogeneous Relativistically Beamed Jet Models
Bruhweiler, F. C.; Miller, H. R.; Worrall, D. M. +4 more
Multifrequency observations are presented of three BL Lac objects, including the first UV measurements of 0912 + 297 and 1219 + 285. An eight day optical flare was measured from 0422 = 004 in which a doubling in visual flux density was noted; other sources displayed smaller daily fluctuations. The 5-15 GHz radio flux from these three objects remai…
EXOSAT and IUE Observations of Contact Binaries
Heise, J.; Vilhu, O.
EXOSAT observations are reported of the contact binaries W UMa, VW Cep, 44t Boo, XY Leo, and V566 Oph and the detached short-period RS CVn stars ER Vul and HD 209943. Complete X-ray light curves were obtained for W UMa, VW Cep and 44t Boo. Nearly simultaneous IUE observations of VW Cep provide important comparisons of the Mg II emission, the UV co…
Measurement of the EUV Spectrum of the Hot White Dwarf Feige 24
Heise, J.; Bleeker, J. A. M.; Brinkman, A. C. +1 more
A high-resolution EUV spectrum of the hot white dwarf Feige 24 in the 190-350 A range is presented. It is demonstrated that, in this region, the measured spectrum deviates strongly from energy distributions calculated from LTE homogeneous model atmospheres for hot DA white dwarfs. The data cannot be fitted with a pure hydrogen spectrum nor with a …