Search Publications
Flatfielding and Photometric Accuracy of The First Hubble Space Telescope Wide Field Camera
Illingworth, Garth D.; Forbes, Duncan A.; Bershady, Matthew A. +2 more
Long exposures with the original Hubble Space Telescope (HST) Wide Field Camera (WFC) through the F555W and F785LP filters show gradients in the background following standard pipeline calibration. We show that these gradients also appear in stellar photometry, and thus must be predominantly the result of inaccurate flatfielding at a level of 10 to…
Satellite Emission Features in Two Seyfert Galaxies: New Evidence That Radio- Quiet AGN Possess Subrelativistic Winds
Stocke, John T.; Sachs, Elise R.; Shull, Michael +1 more
HST/FOS spectra are presented for three bright Seyfert galaxies including one (PG 1351+64) which possesses blue-displaced absorption features in C IV, Si IV, N V, and Lyα (but not in Mg Il) similar to those seen at high redshift in the broad-absorption-line (BAL) QSOs. Several features of the absorptions in PG 1351+64, including variability seen i…
A Deep Atmospheric Eclipse of AL Velorum
Eaton, J. A.
I have obtained new International Ultraviolet Explorer (IUE) observations in 1992 to search for an accretion column in and to analyze an atmospheric eclipse of AL Vel, a low luminosity zeta Aurigae binary. Rich shell spectra recorded at three phases of atmospheric eclipse give column densities and excitation temperatures for the chromospheric gas.…
S MUS B Revisited
Evans, Nancy Remage; Massa, Derck; Teays, Terry J.
IUE high dispersion spectra have been used to investigate the spectral type of the companion of the classical Cepheid S Mus, using Si II and III lines near 1300 A. In addition, the energy distribution from 1200 to 3200 A from IUE low resolution spectra has also been compared with standard stars. The resulting spectral type is B3.5 V (with a redden…
The Binary System Containing the Classical Cepheid T MON
Evans, Nancy Remage; Lyons, Ronald W.
Several new results are presented for the binary system containing the 27d classical Cepheid T Mon. New radial velocities for the Cepheid have been obtained, which confirm the decreasing orbital motion at the current epoch. The spectral type of the companion (B9.8 V) has been determined from an International Ultraviolet Explorer (IUE) l…
The Wind of EG Andromedae is not Dust Driven
Dgani, Ruth; Noriega-Crespo, Alberto; van Buren, Dave
The symbiotic star EG Andromedae has recently been the subject of several studies investigating its wind properties. Late-type giants are usually considered to have winds driven by radiation pressure on dust. Indeed, the derived wind velocity for EG Andromedae is consistent with this model. We point out here that there is no appreciable dust opaci…
Search for CO Absorption Bands in IUE Far-Ultraviolet Spectra of Cool Stars
Carpenter, K. G.; Robinson, R. D.; Gessner, S. E.
Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST) have provided an unambiguous detection of a far-ultraviolet (far-UV) chromospheric continuum on which are superposed strong molecular absorption bands. The absorption bands have been identified by Car…
SN 1991bg: A Type IA Supernova With a Difference
Suntzeff, N. B.; Walker, A. R.; Caldwell, Nelson +28 more
We present 13 spectra and 31 photometric observations covering the first 150 days of SN 1991bg in NGC 4374 (M 84). Although SN 1991bg was a type Ia supernova displaying the characteristic Si II absorption at 6150 A near maximum and the Fe emission lines at late phases, it varied from the well-defined norm for SNe Ia in several important respects. …
Hubble Space Telescope Discovery of Candidate Young Globular Clusters in the Merger Remnant NGC 7252
Robert, Carmelle; Leitherer, Claus; Whitmore, Bradley C. +2 more
New, high-resolution images of the central region of NGC 7252 obtained with the Planetary Camera of the Hubble Space Telescope are presented. NGC 7252 (sometimes referred to as the "Atoms-for-Peace" Galaxy) is a prototypical example of a remnant of two merged disk galaxies. Our most striking result is the discovery of a population of about 40 blue…
Planetary Camera Observations of the Double Nucleus of M31
Holtzman, J. A.; Faber, S. M.; Ewald, S. P. +13 more
V- and I-band HST Planetary Camera images of the great spiral galaxy in Andromeda, M31, show that its inner nucleus consists of two components separated by 0.49". The outer isophotes of the nucleus at 1.4" < r < 3.0" are elongated, but are concentric with the M31 bulge. The nuclear component with the lower surface brightness, P2, is also coi…