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Rotation of dwarf star chromospheres in the ultraviolet.

Hallam, K. L.; Wolff, C. L.

Periodic variations in the ultraviolet fluxes of chromospheric emission line multiplets are investigated for F, G and K stars as evidence of rotational modulation. Vacuum ultraviolet spectra were obtained with the IUE spacecraft for six stars as many as 11 times over the period April 23 to December 3, 1980. Variations in the emission fluxes of the…

The resonnance line of B II in IUE spectra of chemically peculiar stars.

Leckrone, D. S.

A description is presented of high-dispersion spectroscopic observations of eight chemically peculiar stars including Kappa Cnc and Mu Lep, and of one normal comparison star, Nu Cap, in the vicinity of 1362 A. The reported data were obtained with the International Ultraviolet Explorer during the first 15 months of its operation. The initial reduct…

Variability of the continuum and the emission lines in the Seyfert 1 galaxy Akn 120.

Kollatschny, W.; Yorke, H. W.; Fricke, K. J. +1 more

IUE and visual spectrophotometry of Markarian 9, Markarian 10, and 3C 390.3.

Oke, J. B.; Goodrich, R. W.

Ultraviolet spectra from IUE are combined with visual spectra for the three type I Seyfert galaxies Mrk 9, Mrk 10, and 3C 390.3. The 2175 A interstellar feature is measured well enough in Mrk 9 to indicate that the extinction corresponding to E(B-V) = 0.14 + or - 0.04 is in the galaxy. Mrk 10 displays evidence for 2175 A absorption and also yields…

The ultraviolet properties of dust in the Orion Nebula.

Patriarchi, P.; Perinotto, M.; Mathis, J. S. +1 more

The continuum in the Orion Nebula was observed with the IUE at 16 positions varying from 30 arcsec to 5 arcmin in angular separation from the central star Theta(1) Orionis C. The atomic continuum was estimated from the H-beta brightnesses. The remaining scattered starlight was analyzed by multiple-scattering models in which the main parameters are…

Observations of Uranus, Neptune, and Titan by the International Ultraviolet Explorer

Owen, T.; Caldwell, J.; Butterworth, P. S. +3 more

The ultraviolet spectra of Uranus, Neptune, and Titan do not reveal absorption features at 7-A resolution from 2100 to 3200 A. Upper limits of from 1 to 3 A are set for the equivalent widths of narrow absorptions, which corresponds to a CO/H2 mixing ratio less than 2 x 10 to the -4th in the case of Uranus. The slopes of the continuum reflectivitie…

Far UV study on the non-thermal activity in the narrow line galaxies NGC 4507 and NGC 5506.

Maccacaro, T.; Bergeron, J.; Perola, C.

The narrow line high excitation galaxies NGC 4507 and NGC 5506 were observed with IUE satellite in the low resolution mode. The continua of both galaxies, when combined with optical observations, show a flattening at log nu greater than 14.9. The reddening correction cannot be estimated with accuracy. The energy content in the Lyman continuum is l…

The C IV 1550 profile in type 1 Seyfert galaxies.

Gull, T. R.; Boggess, A.; Wu, C. -C.

The paper presents C IV 1550 A line profiles for the type 1 Seyfert galaxies NGC 5548, Mrk 509, NGC 7469, and MCG-2-58-22. Several line broadening mechanisms and theoretical line profiles are considered, and random motion of discrete clouds is ruled out. A spherical ensemble of discrete clouds with steady outflow or inflow produces a logarithmic p…

The γ -ray Emissivity of the Local Interstellar Medium from Correlations with Gas at Intermediate Latitudes

Strong, A. W.; Wolfendale, A. W.

A survey of recent studies of the correlation between γ -rays from latitudes |b| > 10 degrees and gas tracers is presented. Results for the ranges 35-100 MeV and above 100 MeV from the SAS-2 satellite, and for energies between 70 and 5000 MeV from the COS-B satellite, are used to obtain an estimate of the γ -ray emissivity spectrum for all form…

An analysis of the planetary nebula NGC 2867.

Keyes, C. D.; Aller, L. H.; Ross, J. E. +1 more

Spectroscopic observations made with the Anglo-Australian Telescope are combined with IUE data to provide material for a theoretical analysis of NGC 2867. Except for the S II forbidden line, line intensities in the optical region can be represented reasonably well by a simple theoretical model based on Balick's (1975) work. The model is used to as…