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Spatially resolved spectroscopy of WR ring nebulae. II. M 1-67.

Smith, L. J.; Esteban, C.; Manchado, A. +1 more

Detailed, high spatial resolution spectroscopy of the WR ring nebula M1-67 surrounding the WN 8 star WR 124 is presented. Abundances for 4 positions in M1-67 are derived and it is found that N is enhanced by a factor of 4 - 7.5, O is deficient by a factor of 5 - 7.5 and S has a normal H II region abundance. This remarkable abundance pattern leads …

Predicted Profiles of Ultraviolet Interstellar Absorption Lines

York, D. G.; Welty, D. E.; Hobbs, L. M.

In this paper, values of the column density, line width parameter, and velocity are determined for as many components derived from optical interstellar absorption-line profiles of Na I and K I as needed to reproduce the observed high-resolution optical profiles of the D lines of Na I toward eight lightly reddened stars and of the 7698 A line of K …

Boundary-layer temperatures in high accretion rate cataclysmic variables.

Drew, Janet E.; Hoare, Melvin G.

The Zanstra method is used to derive limits on boundary-layer temperatures in eclipsing dwarf novae during outburst and nova-like variables, using the observed He II 1640 and 4686 A recombination lines. It is assumed that all the emission is produced in the wind rather than the accretion disk. This method constrains the boundary-layer temperatures…

First Results from the Goddard High-Resolution Spectrograph: Resolved Velocity and Density Structure in the beta Pictoris Circumstellar Gas

Ebbets, Dennis C.; Trafton, L. M.; Boggess, A. +5 more

A Critical Analysis of the Ultraviolet Temperature Scale of the Helium-dominated DB and DBV White Dwarfs

Vennes, Stephane; Shipman, Harry L.; Thejll, Peter

The temperatures of the hottest of the DB and of some of the variable DBV white dwarfs have been reanalyzed, using a new helium-rich model atmosphere grid and archival IUE data. The grid covers variations in the effective temperature, surface gravity, and trace hydrogen abundance. Significantly lower temperatures than those found by earlier invest…

Lyman- alpha Companions to High-z Quasars

Stockton, Alan; Cowie, Lennox L.; Hu, Esther M. +1 more

We report the results of a narrow-band filter search for Lyα companions to z > 2.8 quasars. Three out of 10 radio-loud quasars are found to have candidate Lyα companions, while no candidates are seen in seven optically selected quasars. Follow-up spectroscopy has confirmed two of the candidates, with one yet to be observed. All the companions l…

NGC 1068: Resolution of Nuclear Structure in the Optical Continuum

Faber, S. M.; Seidelmann, P. Kenneth; Currie, Douglas G. +11 more

An optical continuum image of the Seyfert galaxy NGC 1068 has been obtained with the Planetary Camera on the Hubble Space Telescope as part of the SAO/ERO program. The filter used, F547M, has an effective wavelength and a width of approximately 5470 and 650 A and excludes all discrete emission lines that might be present. The point-spread function…

Coordinated X-Ray, Ultraviolet, and Optical Observations of 3C 120

Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +5 more

The results of 14 observations with EXOSAT and 10 quasi-simultaneous observations with IUE of the Seyfert galaxy 3C 120 are reported. On few epochs, quasi-simultaneous optical spectrophotometry was also obtained, allowing us to derive the energy distribution from the optical to the X-ray band in different intensity states. The X-ray spectra are we…

EXOSAT observations of Cygnus X-1 : study of the soft X-ray excess.

Hasinger, G.; Balucinska, M.

The paper presents results of a spectral analysis of the Cyg X-1 data collected during 1984-1985 by the Medium Energy instrument onboard the Exosat satellite. Emphasis is on two issues: the soft X-ray excess in the range below 3 keV and the iron-line intensity. The presence of a soft component in addition to the high-energy power-law component is …

First Results from the Goddard High-Resolution Spectrograph: The Chromosphere of alpha Tauri

Ebbets, Dennis C.; Brown, Alexander; Walter, Frederick M. +5 more

The K5 III star Alpha Tau was observed with the Goddard High Resolution Spectrograph on November 27, 1990 as part of the Science Assessment Program for the HST. The spectra show intersystem and permitted chromospheric emission lines of semiforbidden C II and Si II, Fe II, Fe I, Ni II, and Co II. Resolved profiles of the semiforbidden C II lines in…