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Variations of the Ultraviolet Fe II and Balmer Continuum Emission in the Seyfert Galaxy NGC 5548
Filippenko, A. V.; Netzer, H.; Shapovalova, A. I. +13 more
We present measurements of the Balmer continuum/Fe II emission blend (the "small blue bump") between 2160 and 4130 A in the Seyfert galaxy NGC 5548. The measurements are from spectra obtained as part of the combined space-based and ground-based monitoring program of this object in 1988- 1989. An iterative scheme is used to determine and subtract t…
Evolution of the Symbiotic Binary System AG Pegasi: The Slowest Classical Nova Ever Recorded
Polidan, Ronald S.; Mikolajewska, Joanna; Slovak, Mark H. +2 more
We present an analysis of new and existing photometric and spectroscopic observations of the ongoing eruption in the symbiotic star AG Pegasi, showing that this binary has evolved considerably since the turn of the century. Recent dramatic changes in both the UV continuum and the wind from the hot component allow a more detailed analysis than in p…
Winds from Accretion Disks: Ultraviolet Line Formation in Cataclysmic Variables
Shlosman, Isaac; Vitello, Peter
Winds from accretion disks in cataclysmic variable stars are ubiquitous. Observations by IUE reveal P Cygni-shaped profiles of high-ionization lines which are attributed to these winds. We have studied the formation of UV emission lines in cataclysmic variables by constructing kinematical models of biconical rotating outflows from disks around whi…
High-Resolution Mid-Infrared Imaging and Astrometry of the Nucleus of the Seyfert Galaxy NGC 1068
Wilson, A. S.; Beichman, C. A.; Braatz, J. A. +2 more
We have used the Goddard Infrared Array Camera to obtain a high resolution (0.7" FWHM) image of the nucleus of NGC 1068 at 12.4 microns. The location of the 12.4 micron peak relative to the peak of the optical continuum has also been determined. The brightest part of the infrared nuclear peak is found to be elongated almost N-S (P.A. ~8^deg^), wit…
The Hubble Space Telescope Quasar Absorption Line Key Project. III. First Observational Results on Milky Way Gas
Schneider, Donald P.; Savage, Blair D.; Sargent, W. L. W. +11 more
We report on absorption by Milky Way disk and halo gas seen in Quasar Absorption Line Key Project measurements of 15 quasars obtained with the Faint Object spectrograph (FOS) of the Hubble Space Telescope (HST). The measurements extend from 1150 to 3270 A for four objects and from 1600 to 3270 A for 11 objects and have a velocity resolution (FWHM)…
HST Observations of NGC 4395, the Least Luminous Seyfert 1 Nucleus: Evidence against the Starburst Hypothesis for Broad-lined Active Galactic Nuclei
Filippenko, Alexei V.; Ho, Luis C.; Sargent, Wallace L. W.
We have used the Hubble Space Telescope to obtain ultraviolet spectra and optical images of the nucleus of NGC 4395, the least luminous and nearest known type 1 Seyfert. The spectrum closely resembles those of normal Seyfert nuclei; narrow emission lines span a wide range of ionization, and the permitted lines have broad wings. If parameterized by…
Wide Field Camera Observations of Baade's Window
Faber, S. M.; Holtzman, Jon A.; O'Neil, Earl J., Jr. +7 more
We have observed a field in Baade's Window using the Wide Field Camera (WFC) of the Hubble Space Telescope (HST) and obtain V- and I-band photometry down to V approximately 22.5. These data go several magnitudes fainter than previously obtained from the ground. The location of the break in the luminosity function suggests that there are a signific…
Quasiperiodic Jovian Radio bursts: observations from the Ulysses Radio and Plasma Wave Experiment
MacDowall, R. J.; Kaiser, M. L.; Desch, M. D. +3 more
The Ulysses flyby of Jupiter has permitted the detection of a variety of quasiperiodic magnetospheric phenomena. In this paper, Unified Radio and Plasma Wave Experiment (URAP) observations of quasiperiodic radio bursts are presented. There appear to be two preferred periods of short-term variability in the Jovian magnetosphere, as indicated by two…
Deceleration of Interstellar Hydrogen at the Heliospheric Interface
Bertaux, Jean-Loup; Clarke, John T.; Lallement, Rosine
High-resolution spectra of nearby stars show absorption lines due to material in the local interstellar cloud. This cloud is deduced to be moving at 26 kilometers per second with respect to the sun, and in the same direction as the "interstellar wind" flowing through the solar system. Measurements by the Ulysses spacecraft show that neutral helium…
The Hot Stellar Component in Elliptical Galaxies and Spiral Bulges. I. The Far-Ultraviolet Spectrum of the Bulge of M31
Ferguson, Henry C.; Davidsen, Arthur F.
We present a spectrum of the bulge of M31 from 1850 A to the Lyman limit measured through a 9" X 116" aperture by the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 space shuttle mission in 1990 December. Apart from airglow, no significant emission features are present in the spectrum. A search for stellar absorption features reveals sever…