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Ultraviolet spectra of a large sample of quasars. I. Data and data reduction.
Gondhalekar, P. M.
Ultraviolet spectrophotometric data on all quasars (Z_e_ > 0.1) obtained with IUE from 1978 to the end of 1986 have been retrieved from IUE archive and re-extracted directly from the photometrically corrected images. A spectrum extraction procedure was used to maximize the signal-to-noise ratio and discriminate against spurious events outside t…
X-ray and optical observations of LDS 587.
Schmitt, J. H. M. M.; Pasquini, L.; Harnden, F. R., Jr. +2 more
During an Exosat observation of the RS CVn star HD 155555 (LDS 587 A) a serendipitous X-ray source (EXO 171224-6653.9) was discovered. This paper presents an analysis of the Exosat and Einstein Observatory (HEAO 2) X-ray observations as well as optical spectra of the serendipitous X-ray source; the X-ray properties of HD 155555 are also discussed.…
Time-dependent study of magnetic fields in comets giacobini-zinner and halley
Neubauer, F. M.; Huebner, W. F.; Slavin, J. A. +4 more
Stationary MHD models are used to analyze the data of magnetic field measurements in comets Giacobini-Zinner and Halley. The contributions of the draping, of changes in the IMF, and of turbulence are separated and extended patches of unidirectional field regions are identified. A time-dependent MHD simulation of the nonstationary flow following a …
Comparison of Einstein and EXOSAT Observations of SS 433
Band, David L.
Observations with the Einstein telescope which show SS 433 to be a flaring X-ray source with a variable power-law spectrum are compared to Exosat observations which show a relatively quiescent X-ray spectrum with a prominent blueshifted iron line consistent with thermal emission in the jets. Models to explain the differences between the two studie…
Chromospherically Active Stars. VI. HD 136901 = UV CrB: A Massive Ellipsoidal K Giant Single-Lined Spectroscopic Binary
Kirkpatrick, J. Davy; Fekel, Francis C.; Strassmeier, Klaus G. +1 more
The variable star HD 136901 = UV CrB is a chromospherically active K2 III single-lined spectroscopic binary with an orbital period of 18.665 days. It has modest-strength Ca H and K emission and UV features, while H-alpha is a strong absorption feature containing little or no emission. The inclination of the system is 53 + or - 12 deg. The v sin i …
The IUE spectral atlas of two normal B stars : pi Ceti and nu Capricorni (125-198 nm).
Lanz, T.; Borsenberger, J.; Artu, M. -C.
The ultraviolet spectra of two main-sequence B stars, Pi Cet (HD 17081) and Nu Capricorni (HD 193432) recorded by the IUE satellite have been used to elaborate a reference atlas, with line identification, in the low wavelength range 125-198 nm. To obtain realistic identifications and to select the dominant contributors in blends, a synthetic calcu…
Rotational modulation of hydrogen Lyman alpha flux from 44i Bootis.
Vilhu, O.; Neff, J. E.; Rahunen, T.
Observations with IUE that cover the entire 6.4 hr orbital cycle of the late-type contact binary 44i Bootis are presented. Intrinsic stellar hydrogen Lyman alpha emission flux was determined from low-resolution IUE spectra, compensating for geocoronal emission and for interstellar absorption. The variation of the stellar Lyman alpha emission flux …
Ultraviolet Observations of the Planetary Nebula NGC 2242
Garnett, Donald R.; Dinerstein, Harriet L.
We present IUE observations of the high-ionization planetary nebula NGC 2242. The ultraviolet spectrum exhibits stong emission lines of C IV, He II, C III], and [Ne IV], plus weaker emission from O IV and N IV. We have also obtained narrow-band imaging of NGC 2242 in the He II 4686 A emission line; comparison of the λ 4686 flux from this image wit…
The UV Spectrum of Pluto-Charon: IUE Observations from 2600 to 3100
Stern, S. A.; Skinner, T. E.; Trafton, L. M. +2 more
Observations of the UV spectra of the Pluto-Charon system were obtained between 1987 and 1988 using the large aperture of the IUE long-wavelength prime spectrograph. At the resolution and SNR of the data, no gas-phase spectral identifications were made. The present data indicate a geometric albedo of 0.35 + or - 0.05. Curve fitting the geometric a…
The X-Ray Variability of PKS:2155-304 - a Power Spectrum Analysis
Maraschi, L.; Tagliaferri, G.; Stella, L. +2 more
The bright BL Lac object PKS 2155-304 was observed with EXOSAT 9 times between 1983 and 1985 for a total of 80 hours. During some observations the source appeared stable, while during others, flare-like activity was observed, the intensity doubling in less than an hour. Here we present a power spectrum analysis of the 3 brightest observations. Sig…