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UV and optical spectroscopy of OB stars in M 31 and M 33.
Bianchi, L.; Hutchings, J. B.; Massey, P.
IUE UV spectra and MMT blue spectra have been obtained for 'normal' OB supergiant stars in M31 and M33. The authors classify the stars as late O to early B. UV and visible fluxes yield consistent values for the effective temperature, bolometric magnitudes, and extinction for the stars. The UV resonance lines have very low outflow velocities compar…
X-ray luminosity and the hydrogen-line ratios of quasars and Seyfert galaxies.
Kriss, G. A.
New observations of the Ly-alpha/H-alpha ratio in a set of X-ray-selected active galactic nuclei and an archival study of International Ultraviolet Explorer (IUE) observations of Ly-alpha in low-redshift quasars and Seyfert galaxies have been used to form a large sample (49 objects) for studying the influence of soft X-rays on the enhancement of B…
He 2-36 : a planetary nebula with a high-velocity jet ?
Feibelman, W. A.
The ultraviolet spectrum of the planetary nebula He2-36 was observed in the low-dispersion mode of the IUE. Strong emission lines of C III], He II, and C IV are observed, as well as some weak lines and a moderately strong stellar continuum, suggesting a hot companion to the visual A2 III central star. The extinction to He2-36 was determined from t…
Chromospherically active stars. I. HD 136905.
Fekel, F. C.; Africano, J. L.; Quigley, R. +3 more
The variable star HD 136905, recently designated GX Librae, is a chromospherically active K1 III single-lined spectroscopic binary with a period of 11.1345 days. It has moderate strength Ca II H and K and ultraviolet emission features, while Hα is strongly in absorption. The inclination of the systems is 58°±17° and the unseen secondary is most li…
Comet Bowell 1980b
Feldman, P. D.; A'Hearn, M. F.; Schleicher, D. G. +2 more
The authors have carried out optical filter photometry and optical and ultraviolet spectrophotometry of Comet Bowell over the period November 1980 - June 1982. They have observed emission by OH at heliocentric distances to nearly 5 AU preperihelion with the OH emission implying a production rate which decreased, but with outbursts, as the comet ap…
VW HYI : the white dwarf revealed.
Szkody, P.; Mateo, M.
Nonsimultaneous IUE, optical, and near-IR observations of VW Hyi at quiescence are presented. Using these and UV data from other investigations, a broad feature in the ultraviolet is identified with L-alpha absorption. The presence and width of the line imply that (1) the white dwarf in VW Hyi is directly visible in the UV and (2) the effective te…
IUE spectroscopy of the degenerate components in the Hyades close binaries V471 Tauri and HZ 9.
Sion, E. M.; Guinan, E. F.
Effective temperatures and gravities have been determined for the degenerate components in the Hyades close binaries V471 Tauri and HZ9 from model atmosphere analysis of IUE ultraviolet spectra. For V471 Tauri, T(e) = 35,000 K and log g is about 8. For HZ9, T(e) = 20,000 K and log g = 8. Both systems contain DA2 white dwarfs. No photospheric metal…
Ripple correction of high-dispersion IUE spectra: blazing echelles.
Barker, P. K.
An iterative differential correcion technique designed to remove the blaze function of an echelle grating directly from observed spectral data is mathematically defined and applied to high-dispersion images acquired with the International Ultraviolet Explorer. Quantitative measurements of ripple correction accuracy demonstrate that the technique i…
The depletion of pre-interstellar matter and an examination of NI II oscillator strengths.
Cardelli, J. A.
IUE observations of the B2.5 V star α Sco B have been used to analyze the absorption lines that arise in the circumstellar shell around the M1.5 Iab star α Sco A. In addition to resonant lines of Fe II, Si II, Mg II, Mn II, and S II, most of the resonant lines of Ni II are also present at strengths above 40 mÅ. A fit of these Ni II lines to a curv…
The nature of radio-quiet QSO's VLA observations of 0026+129, 0205+024 and 1351+640.
Sitko, M. L.; Rudnick, L.; Stein, W. A.
VLA maps of 'radio-quiet' QSOs are reported. Extended emission is found on linear scales of about 10 kpc, larger than that observed in Seyfert galaxies, but smaller than most radio-loud objects. The spectral properties of some radio-quiet objects are also very similar to those of radio-quiet Seyfert galaxies such as NGC 4151; some radio-quiet QSOs…