Search Publications
An Ultraviolet Study of the Short-Period Binary OO Aquilae
Guinan, Edward F.; Hrivnak, Bruce J.; Ribas, Ignasi +1 more
OO Aql is a rare W UMa-type eclipsing binary in which the two solar-type stars may have only recently evolved into contact. The binary has an unusually high mass ratio (0.84) and a relatively long orbital period (0.506 days) for its spectral type (mid-G). Twelve ultraviolet spectra of OO Aql were obtained in 1988 with the International Ultraviolet…
The Gravitational Lens Candidate FBQ 1633+3134
White, Richard L.; Gregg, Michael D.; Morgan, Nicholas D. +2 more
We present our ground-based optical imaging, spectral analysis, and high-resolution radio mapping of the gravitational lens candidate FBQ 1633+3134. This z=1.52, B=17.7 quasar appears double on CCD images with an image separation of 0.66" and a relatively constant flux ratio of ~3:1 across B, V, R, and I filters. A single 0.27 mJy radio source is …
Young Clusters in the Magellanic Clouds. II.
Da Costa, G. S.; Bessell, M. S.; Keller, Stefan C.
We present the results of a quantitative study of the degree of extension to the boundary of the classical convective core within intermediate-mass stars. The basis of our empirical study is the stellar population of four young populous clusters in the Magellanic Clouds that has recently been detailed by Keller, Bessell, & Da Costa. The sample…
Infrared Space Observatory Short Wavelength Spectrometer Observations of V1425 Aquilae (Nova Aquila 1995)
Morisset, C.; Humphreys, R. M.; Gehrz, R. D. +19 more
We present observations of the classical nova V1425 Aquilae (Nova Aquila 1995) with the Infrared Space Observatory's (ISO) Short Wavelength Spectrometer, the Isaac Newton Telescope's Intermediate Dispersion Spectrograph, and the International Ultraviolet Explorer's Short-Wavelength Primary Spectrograph. Analysis of He II (1640 Å) development const…
The Tolman Surface Brightness Test for the Reality of the Expansion. III. Hubble Space Telescope Profile and Surface Brightness Data for Early-Type Galaxies in Three High-Redshift Clusters
Sandage, Allan; Lubin, Lori M.
Photometric data for 34 early-type galaxies in the three high-redshift clusters Cl 1324+3011 (z=0.76), Cl 1604+4304 (z=0.90), and Cl 1604+4321 (z=0.92), observed with the Hubble Space Telescope (HST) and with the Keck 10 m telescopes by Oke, Postman, & Lubin, are analyzed to obtain the photometric parameters of mean surface brightness, magnitu…
Hydrodynamic Simulations for the Nuclear Morphology of NGC 4314
Ann, H. B.
We performed smoothed particle hydrodynamic (SPH) simulations to study the nuclear morphology of the barred galaxy NGC 4314. We have constructed the mass models based on the results of a profile decomposition into disk, bulge, and bar components. Our models have three different nuclear structures according to the assumption about the nuclear bar: …
CLASS B0739+366: A New Two-Image Gravitational Lens System
Pearson, T. J.; Blandford, R. D.; Koopmans, L. V. E. +10 more
We present the discovery of CLASS B0739+366, a new gravitational lens system from the Cosmic Lens All-Sky Survey. Radio imaging of the source with the Very Large Array shows two compact components separated by 0.54", with a flux density ratio of ~6:1. High-resolution follow-up observations using the Very Long Baseline Array (VLBA) at 1.7 GHz detec…
A High-Resolution H I Study of the Interstellar Medium Local to HD 193793
Arnal, E. Marcelo
A 2° field centered at the optical position of the Wolf-Rayet (WR) star HD 193793 (≡ WR 140) was surveyed in the H I 21 cm line and in the 1420 MHz radio continuum, using the Dominion Radio Astrophysical Observatory interferometer. The aim of this observations was to look for evidence of an interaction between the WR star and its local interstella…
Barnard's Merope Nebula Revisited: New Observational Results
Simon, Theodore; Herbig, G. H.
IC 349 is a small, fan-shaped reflection nebula located only 30" from 23 Tau; its nucleus is, by a factor 15, the brightest area of the Pleiades nebulosity. We propose that IC 349 is a fragment of the Taurus-Auriga molecular cloud that has been encountered by the Pleiades in that cluster's southward motion and is being illuminated and shaped by th…
Hubble Space Telescope-NICMOS Observations of M31'S Metal-Rich Globular Clusters and Their Surrounding Fields. I. Techniques
Rich, R. Michael; Jablonka, Pascale; Frogel, Jay A. +6 more
Astronomers are always anxious to push their observations to the limit-basing results on objects at the detection threshold, spectral features barely stronger than the noise, or photometry in very crowded regions. In this paper we present a careful analysis of photometry in crowded regions and show how image blending affects the results and interp…