Search Publications
The Mid- and Far-Infrared Spectral Energy Distribution of Seyfert Galaxies
Rodriguez Espinosa, J. M.; Perez Garcia, A. M.; Santolaya Rey, A. E.
Hubble Space Telescope Eclipse Observations of the Nova-like Cataclysmic Variable UX Ursae Majoris
Horne, Keith; Hubeny, Ivan; Long, Knox S. +4 more
We present and analyze Hubble Space Telescope observations of the eclipsing nova-like cataclysmic variable UX UMa obtained with the Faint Object Spectrograph. Two eclipses each were observed with the G160L grating (covering the ultraviolet waveband) in 1994 August and with the PRISM (covering the near-ultraviolet to near-infrared) in November of t…
Evidence in Support of the ``Nanoflare'' Picture of Coronal Heating from SUMER Data
Judge, P. G.; Wilhelm, K.; Schühle, U. +3 more
We study high signal-to-noise profiles of O IV emission lines obtained using the SUMER instrument on SOHO. Data for the quiet Sun obtained close to the disk center and at the solar limb were acquired. After careful data processing in which disk data were analyzed differentially against limb data, we find a systematic correlation between a density-…
Inclined Gas Disks in the Lenticular Seyfert Galaxy NGC 5252
Wilson, Andrew S.; Morse, Jon A.; Tsvetanov, Zlatan I. +1 more
We discuss the morphology and kinematics of the extended gas in the type 2 Seyfert galaxy NGC 5252 based on Hubble Space Telescope (HST) WFPC2 continuum and emission-line images (including a new [O III] λ5007 image) and a ground-based Fabry-Perot (F-P) velocity map of the ionized gas. The fine-scale morphology of the ionized gas in this galaxy's v…
Random Damping and Frequency Reduction of the Solar F Mode
Kosovichev, A. G.; Murawski, K.; Duvall, T. L., Jr.
We present observations showing that the frequency of the high-degree f-mode is significantly lower than the frequency given by the simple dispersion relation, ω2=gk , and that the line width grows with the wavenumber k. We attempt to explain that this behavior is the result of the interaction with granulation, which we model as a rando…
Differences between the Optical/Ultraviolet Spectra of X-Ray Bright and X-Ray Faint QSOs
Green, Paul J.
We contrast measurements of composite optical and ultraviolet (UV) spectra constructed from samples of QSOs defined by their soft X-ray brightness. X-ray bright (XB) composites show stronger emission lines in general, but particularly from the narrow-line region. The difference in the [O III]/Hβ ratio is particularly striking, and is even more so …
Tomographic Analysis of Hα Profiles in HDE 226868/Cygnus X-1
Shafter, A. W.; Gies, D. R.; Bagnuolo, W. G. +3 more
We present high-quality Hα spectra of the massive X-ray binary HDE 226868 = Cyg X-1 that were made in 1985 and 1986. We measured radial velocities using the He I λ6678 line, and we use the resulting orbital solution together with a Hipparcos light curve of the ellipsoidal variation to arrive at a revised period estimate of P = 5.59977 +/- 0.00002 …
Hubble Space Telescope Observations of an Accreted Silicon SPOT on the White Dwarf in V471 Tauri
Bond, Howard E.; Sion, Edward M.; Saffer, Rex A. +2 more
We have used the Hubble Space Telescope's (HST) Goddard High-Resolution Spectrograph to detect a photospheric metallic absorption line, Si III λ1206, in the spectrum of the magnetic white dwarf component of the Hyades precataclysmic binary V471 Tauri. The Si III feature is modulated on the soft X-ray/EUV/optical 9.25 minute rotational period of th…
Galaxy Morphology from NICMOS Parallel Imaging
Gardner, Jonathan P.; Teplitz, Harry I.; Heap, Sara R. +1 more
We present high-resolution Near-Infrared Camera and Multiobject Spectrometer images of random fields obtained in parallel to other Hubble Space Telescope observations. We present galaxy number counts reaching H1.6=24. The H1.6-band galaxy counts show good agreement with the deepest I- and K-band counts obtained from ground-ba…
Near-Infrared Observations of a Redshift 4.92 Galaxy: Evidence for Significant Dust Absorption
Illingworth, G. D.; Franx, M.; Matthews, K. +2 more
Near-infrared imaging and spectroscopy have been obtained of the gravitationally lensed galaxy at z=4.92 discovered in Hubble Space Telescope (HST) images by Franx et al. Images at 1.2, 1.6, and 2.2 µm show the same arc morphology as the HST images. The spectrum with resolution λ/Δλ~70 shows no emission lines with equivalent width stronger t…