Search Publications
The Ultraviolet Spectrum of Scorpius X-1 as Observed by IUE: 1978--1988
Raymond, J. C.; Kallman, T. R.; Vrtilek, S. D.
The IUE observations of Sco X-1 taken prior to September 1988 are summarized. These data are tested for variability associated with orbital motion and for correlations between the various observables. The continuum spectra are fitted to simple models for accretion disk atmospheres which demonstrate that X-ray heating dominates the outer regions of…
Does SV Centauri Harbor an Accretion Disk?
Linnell, Albert P.; Scheick, Xania
Light synthesis simulation of SV Cen UBV photometry by Drechsel et al. (1982) exhibits appreciable residuals. These residuals, together with large Roche model overcontact but also large calculated intercomponent temperature difference, suggests that the light synthesis Roche model is inapplicable. The substantial rate of period change indicates ra…
First Results from the Goddard High-Resolution Spectrograph: Ultraviolet Spectra of a Starburst Knot in NGC 1068
Hutchings, J. B.; Bruhweiler, F.; Boggess, A. +7 more
We present UV spectroscopy of a circumnuclear starburst knot in the Seyfert 2 galaxy NGC 1068. The spectrum shows the presence of several thousand O and B stars which appear to have formed about 3 million years ago. We also discuss the extinction and interstellar medium in the line of sight.
Observations That Link Infrared Cirrus and Ultraviolet Extinction
Tapia, Mauricio; Hecht, James H.; Hackwell, John A.
Results are presented of UV extinction measurements of 17 stars in the open cluster IC 4665 and of four stars in the open cluster NGC 1647, showing that the UV extinctions of the two clusters stars have different properties. Whereas the stars in NGC 1647 cluster are typical of general interstellar space, the stars in IC 4665 have a small 'linear' …
Faint Object Camera Observations of a Globular Cluster Nova Field
Anderson, Scott F.; Jakobsen, Peter; Bohlin, Ralph C. +2 more
The Faint Object Camera onboard Hubble Space Telescope has obtained U and B images of the field of Nova Ophiuchi 1938 in the globular cluster M14 (NGC 6402). The candidate for the quiescent nova suggested by Shara et al. (1986) is clearly resolved into at least six separate images, probably all stellar, in a region of 0.5 arcsec. Although two of t…
Sulfur-bearing Ions in the Ionosphere of Comet Halley
Reme, H.; Korth, A.; Lin, R. P. +3 more
This paper presents the radial density profiles of the ions corresponding to 35, 45, 47, and 47 amu, inside the ionopause of Comet Halley, obtained by the heavy ion analyzer PICCA on board the Giotto spacecraft. A photochemical model of the outflowing atmosphere/ionosphere, which emphasizes the sulfur chemistry in an H2O-dominated atmosphere, is u…
X-Ray Observations of the Bright Seyfert Galaxy IC 4329A
Singh, K. P.; Rao, A. R.; Vahia, M. N.
We have performed a detailed analysis of the broad-band (0.1-25 keV) EXOSAT observations of the high-luminosity, nearby Seyfert type I galaxy IC 4329A. The observations were carried out on two occasions, 1984 July and 1985 July. The X-ray luminosity decreased by ~35% over one year. A significant short-term variability where the intensity decreased…
Hubble Space Telescope Wide-Field/Planetary Camera Images of Saturn
Faber, S. M.; Ewald, S. P.; Hester, J. J. +12 more
Saturn was recorded in blue, green, and 'red' light with the Wide-Field/Planetary Camera aboard the Hubble Space Telescope. Owing to relatively high signal levels over most of the planet's image, a dramatic improvement in the visibility of image detail was achieved by deconvolving the raw images, which had suffered severely from the spherical aber…
A Search for Circumstellar Dust around HR 10, a Proposed beta Pictoris Star
Cheng, Kwang-Ping; Grady, C. A.; Bruhweiler, Frederick C.
Archival IRAS data and recent IUE observations of the A shell star HR 10 (HD 256) are presented. HR 10 is detected in the IRAS Faint Source Survey and ADDSCAN data at 12 and 25 microns and marginally detected at 60 microns. The IUE data indicate a spectral type of A2 with 0.1 mag of UV selective extinction following a galactic average extinction l…
IUE Observations of NGC 1068: The Extended High-Ionization Emission Region
Bruhweiler, F. C.; Truong, K. Q.
UV emission morphology of the inner disk of NGC 1068 reveals extremely strong emission of the highly ionized species, N V λ1240, C IV λ 1550, and He II λ1640 in regions of distances up to 25"(2.5 kpc) from the nucleus. The strong emission from these species cannot be due to photoionization from OB stars and requires either photoionization from the…