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A Hubble Space Telescope Faint Object Spectrograph Survey for Broad Absorption Lines in a Sample of Low-redshift Weak [O III] Quasi-stellar Objects
Turnshek, David A.; Espey, Brian R.; Monier, Eric M. +1 more
The study by Boroson & Meyers led to the suggestion that radio-quiet QSOs with weak [O III] and strong Fe II emission spectra form a class of QSOs that has a high probability of exhibiting broad absorption lines (BALs) in their spectra. Furthermore, they argued that since narrow-line [O III] emission is almost certainly emitted isotropically, …
SUMER Observations of the Quiet Solar Atmosphere: The Network Chromosphere and Lower Transition Region
Wilhelm, Klaus; Carlsson, Mats; Judge, Philip
We examine spectral properties of the network chromosphere and lower transition region from the SUMER instrument on the SOHO spacecraft, using time-series data sets discussed in an accompanying Letter by Carlsson, Judge, & Wilhelm. The data were obtained early in the mission with no tracking of solar features and so cannot generally be used to…
Detailed Non-LTE Model Atmospheres for Novae during Outburst. I. New Theoretical Results
Baron, E.; Shore, Steven N.; Hauschildt, Peter H. +3 more
We present new, detailed non-LTE (NLTE) calculations for model atmospheres of novae during outburst. This fully self-consistent NLTE treatment for a number of model atoms includes 3922 NLTE levels and 47,061 NLTE primary transitions. We discuss the implication of departures from LTE for the strengths of the lines in nova spectra. The new results s…
GHRS Monitoring of the Outflowing Material in NGC 4151
Morris, Simon L.; Hutchings, John B.; Weymann, Ray J. +1 more
We present the results of a program to monitor the absorption lines in the spectrum of the Seyfert 1 galaxy NGC 4151 caused by outflowing gas from the nucleus. Spectral observations were taken in the UV with the GHRS and FOS of HST. GHRS G160M and G270M exposures were taken of the wavelength regions centered on C IV and Mg II, respectively, extend…
The Abundance of Interstellar Krypton
Meyer, David M.; Cardelli, Jason A.
We present high signal-to-noise ratio HST Goddard High Resolution Spectrograph (GHRS) observations of the weak interstellar Kr I λ1236 absorption toward the stars τ CMa, κ Ori, ɛ Ori, λ Ori, δ Sco, ω1 Sco, ɛ Per, and ζ Per. In combination with previous GHRS measurements of Kr I in two other sight lines (ζ Oph and 1 Sco), these new obser…
Doppler Shifts and Nonthermal Broadening in the Quiet Solar Transition Region: O VI
Wilhelm, K.; Lemaire, P.; Mariska, J. T. +1 more
Using observations from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) experiment flown on the Solar and Heliospheric Observatory (SOHO) spacecraft, we have measured Doppler wavelength shifts and nonthermal broadening in the 1032 and 1038 Å emission lines of O VI and the 1036 and 1037 Å emission lines of C II. Near Sun center the …
New Wavelength Determinations of Mid-Infrared Fine-structure Lines by Infrared Space Observatory Short Wavelength Spectrometer
Lutz, D.; Heras, A. M.; Beintema, D. A. +18 more
We report accurate new wavelengths for 29 mid-infrared ionic fine-structure lines, based on observations with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). Our results originate from observations of NGC 7027, NGC 6543, NGC 6302, the Circinus galaxy, Sgr A West, and W51 IRS 2. The obtained accuracies (λ/Δλ) …
High-Resolution Ultraviolet Observations of the Highly Ionized Interstellar Gas toward Radio Loops I and IV
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D.
We present new Goddard High-Resolution Spectrograph (GHRS) echelle observations of the high ionization lines of Si IV, C IV, and N V toward HD 119608, a halo star at d = 4.1 kpc behind the Loop I and IV supernova remnants. Absorption along the path to HD 119608 makes it possible to study energetic processes that may result in the flow of gas into …
The CO2/CO Abundance Ratio in 1P/Halley and Several Other Comets Observed by IUE and HST
Weaver, Harold A.; Feldman, Paul D.; Tozzi, Paolo +1 more
We report the detection of CO Cameron band emission in the ultraviolet spectra of four moderately active comets (including 1P/Halley) obtained by the International Ultraviolet Explorer (IUE) satellite. The motivation was the observation of Cameron band emission, a tracer of the CO2 production rate, in the spectra of two comets observed …
Hipparcos, VLA, and CCD Observations of Cygnus OB2 No. 5: Solving the Mysteryof the Radio ``Companion''
Badiali, M.; Cardini, D.; Emanuele, A. +4 more
We present accurate optical and radio astrometry for the unresolved contact binary system Cyg OB2 No. 5 and its weaker component to the northeast. While the radio and optical positions of the primary component (taken to be the unresolved contact binary) agree within observational error (~70 mas), we find that the weaker radio component does not ag…