Search Publications
A Database for Galaxy Evolution Modeling
Walborn, Nolan R.; Parker, Joel Wm.; Robert, Carmelle +77 more
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of the spectra and evolution of galaxies. A broad variety of empirical and theoretical data are discussed here, and the data are made fully available in the AAS CD-ROM Series, Vo. 7. Several empirical stellar libraries are part of th…
A Supergiant-Dominated Starburst in the Nucleus of NGC 4569
Keel, William C.
The Virgo spiral NGC 4569 has a very compact optical nucleus whose spectrum is highly composite, which strong Balmer absorption indicating that A stars dominate the optical light. Recent HST imaging shows that the nucleus is extremely compact in the mid-ultraviolet, so that either there must be a central AGN or an extraordinarily luminous and comp…
The Spectrum of the Planetary Nebula NGC 6790
Feibelman, Walter A.; Hyung, Siek; Aller, Lawrence H.
International Ultraviolet Explorer (IUE) and optical region spectroscopic observations are presented for the medium excitation planetary nebula (PN), NGC 6790, which displays a rich spectrum permitting application of several diagnostic ratios and the calculation of a number of ionic concentrations, N(ion)/N(H+). NGC 6790 seems to be a relatively y…
The White-Dwarf Companions of 56 Persei and HR 3643
Bergeron, Pierre; Simon, Theodore; Landsman, Wayne
We have obtained low-dispersion IUE spectra of the stars 56 Persei (F4 V) and HR 3643 (F7 II), as part of a survey of late-type stars with a 1565A flux excess in the TD-1 ultraviolet sky survey. The IUE spectrum of each star reveals the presence of a hot white dwarf companion. We fit the Ly-alpha profile and ultraviolet continuum using pure hydrog…
An O VIII Sequence for Planetary Nebula Nuclei
Feibelman, Walter A.
The detection of O VIII emission lines in ultraviolet and optical spectra of high-excitation planetary nebula central stars suggests an "O VIII Sequence" for these object. Emission lines of O VII are also detected. Seven out of ten central stars for these planetaries are known to be nonradial g-mode pulsators. The stars form a narrow strip when pl…
The Diverse Optical/Ultraviolet Spectra of the Globular Cluster X-ray Sources in NGC 7078 and NGC 6712
Anderson, Scott F.; Margon, Bruce; Downes, Ronald A.
Among the about one dozen luminous X-ray bursters in the cores of globular clusters, only three have optical/UV counterparts unambiguously identified. We have observed two of these counterparts spectroscopically with the low resolution optical and UV gratings of the Faint Object Spectrograph (FOS) aboard the Hubble Space Telescope (HST), yielding …
The Iron Abundance of IOTA Herculis
Grigsby, James A.; Mulliss, Christopher L.; Baer, Gretchen M.
We have obtained coadded, high-resolution IUE spectra of Iota Herculis (B3 IV) in both the short-wavelength (SWP) and long-wavelength (LWP) regions. LTE synthetic spectra with a resolution identical to that of IUE were produced with the Kurucz model atmosphere and spectral synthesis codes ATLAS9/SYNTHE. Model parameters were chosen from the litera…
UV Observations of Three LMC Be-Star/X-ray Binaries
Hauschildt, P. H.; Cowley, A. P.; Schmidtke, P. C. +4 more
This paper describes IUE ultraviolet observations of three Be-star/X-ray binaries in the LMC: CAL 9, CAL E, and RX J0520.5-6932. Because the optical spectra show evidence of an overlying continuum source, ultraviolet spectra were obtained to further investigate its properties, but no UV emission lines are found. The UV spectra have been compared t…
Camera Artifacts in IUE High-Dispersion Spectra
Crenshaw, D. Michael; Bruegman, Ottow W.; Johnson, Rita +1 more
Sky-background images obtianed with the International Ultraviolet Explorer (IUE) have been analyzed to identify camera artifacts in high-dispersion point-source spectra observed through the large aperture. The camera artifacts are artificial emission features that are apparent in all IUE spectra with exposure times longer than about one hour. The …