Search Publications
HST Images of Very Compact Blue Galaxies at Z approximately 0.2
Bershady, Matthew A.; Majewski, Steven R.; Koo, David C. +2 more
We present the results of HST Wide-Field Camera (WFC) imaging of seven very compact, very blue galaxies with B <= 21 and redshifts z ~ 0.1 to 0.35. Based on deconvolved images, we estimate typical half-light diameters of ~0.65", corresponding to ~1.4 h^-1^ kpc at redshifts z~0.2. The average rest frame surface brightness within this diameter is…
HD 129333: The Sun in Its Infancy
Guinan, Edward F.; Dorren, J. David
HD 129333 is a remarkable young, nearby solar-type G star which offers a unique opportunity of studying the properties of the Sun at a time very shortly after in arrived on the main sequence. Its space motion suggest that it is a member of the Pleiades moving group, with an age of approximately 70 Myr; its lithium abundance is consistent with this…
Galaxies with Extreme Infrared and Fe II Emission. II. IRAS 07598+6508: A Starburst/Young Broad Absorption Line QSO
Lipari, Sebastian
In this paper we investigate the nuclear properties of the extreme IR- Fe II emitters IRAS 07598+6508 by means of UV-optical spectroscopy, and IR photometry. The features shown in the UV region (by the IUE spectrum of IRAS 07598+6508) are very similar to those obtained for high-redshift low-ionization BAL QSOs (i.e., they show a strong blend of br…
Tomographic Separation of Composite Spectra. II. The Components of 29 UW Canis Majoris
Wiggs, Michael S.; Gies, Douglas R.; Bagnuolo, William G., Jr. +2 more
We have analyzed the UV photospheric lines of 29 CMa, a 4.39 day period, double-lined O-type spectroscopic binary. Archival data from International Ultraviolet Explorer (IUE)(28 spectra well distributed in oribital phase) were analyzed with several techniques. We find that the mass ratio is q = 1.20 +/- 0.16 (secondary more massive) based on three…
The Abundance of Interstellar Oxygen toward Orion: Evidence for Recent Infall?
Meyer, David M.; Jura, M.; Cardelli, Jason A. +1 more
We present high S/N (greater than 800) Goddard High-Resolution Spectrograph (GHRS) observations of the weak interstellar O I lambda 1356 absorption in the low-density sight lines toward iota Ori and kappa Ori. By comparing these data with observations toward more reddened stars, we find no evidence of density-dependent depletion from the gas phase…
Galaxies with Extreme Infrared and Fe II Emission. I. Markarian 231: The Signature of a Young Infrared QSO
Colina, Luis; Macchetto, F.; Lipari, Sebastian
We investigate the ultraluminous IR Galaxy/QSO Mrk 231 by means of long-slit optical spectroscopy, high spatial resolution broad-band optical imaging and UV IUE spectra. The spectrum shows an extreme Fe II optical emission (Fe II_OPT_/Hβ ~ 8), broad Balmer and Na ID lines, weak high-excitation lines, double-peaked optical narrow emission lines wit…
Non--LTE Model Atmosphere Analysis of Nova Cygni 1992
Sonneborn, G.; Hauschildt, P. H.; Shore, S. N. +3 more
We use spherically symmetric non-local thermodynamic equilibrium (non-LTE), line-blanketed, expanding model atmospheres to analyze the International Ultraviolet Explorer (IUE) and optical spectra of Nova Cygni 1992 during the early phases of its outburst. We find that the first IUE spectrum obtained just after discovery on 1992 February 20, is bes…
The Coronal Electron Density Distribution Determined from Dual-Frequency Ranging Measurements during the 1991 Solar Conjunction of the ULYSSES Spacecraft
Bird, M. K.; Asmar, S. W.; Volland, H. +3 more
Dual-frequency ranging and Doppler measurements were conducted in support of the Ulysses Solar Corona Experiment (SCE) at and around the spacecraft's first solar conjunction in 1991 August. The differential group delay time between range codes on the two downlink carrier signals at the wavelengths 13.1 and 3.6 cm, a direct measure of the total ele…
The Discovery of 8.7 Second Pulsations from the Ultrasoft X-Ray Source 4U 0142+61
Mereghetti, S.; Stella, L.; Israel, G. L.
We discovered a periodicity at about 8.7s from the X--ray sources 4U0142+61, previously considered a possible black hole candidate on the basis of its ultrasoft spectrum. The pulsations are visible only in the 1--4 keV energy range, during an observation obtained with the EXOSAT satellite in August 1984. A search for delays in the pulse arrival ti…
Hubble Space Telescope Goddard High-Resolution Spectrograph Observation of U Geminorum during Quiescence: Evidence for a Slowly Rotating White Dwarf
Szkody, Paula; Sion, Edward M.; Long, Knox S. +1 more
We have obtained a pair of consecutive far-ultraviolet Goddard High-Resolution Spectrograph (GHRS) exposures of the Si IV region of the dwarf nova U Geminorum in early quiescence, 8 days after its return to optical quiescence when the underlying white dwarf dominates the ultraviolet light of the system. Our GHRS observation revealed a fully resolv…