Search Publications
Constraints on the Ionization Balance of Hot-Star Winds from FUSE Observations of O Stars in the Large Magellanic Cloud
Sonneborn, G.; Massa, D.; Hutchings, J. B. +1 more
We present Far Ultraviolet Spectroscopic Explorer (FUSE) spectra for 25 O stars in the Large Magellanic Cloud. We analyze wind profiles for the resonance lines from C III, N III, S IV, P V, S VI, and O VI in the FUSE range using a ``Sobolev with exact integration'' method. In addition, the available data from either IUE or the Hubble Space Telesco…
Massive Star Formation in a Gravitationally Lensed H II Galaxy at z = 3.357
Stern, D.; Sargent, W. L. W.; Rosati, P. +9 more
The Lynx arc, with a redshift of 3.357, was discovered during spectroscopic follow-up of the z=0.570 cluster RX J0848+4456 from the ROSAT Deep Cluster Survey. The arc is characterized by a very red R-K color and strong, narrow emission lines. Analysis of HST WFPC2 imaging and Keck optical and infrared spectroscopy shows that the arc is an H II gal…
Method for Spot Detection on Solar-like Stars
Silva, Adriana V. R.
As a planet eclipses its parent star, a dark starspot may be occulted, causing a detectable variation in the light curve. This work describes how features on the surface of a solar-like star can be studied by using planetary transits. Images of the Sun were used in order to simulate such transits, with the planet being modeled as a dark disk at va…
The Canada-UK Deep Submillimeter Survey. VI. The 3 Hour Field
Ivison, R. J.; Clements, D. L.; Dunne, L. +6 more
We present the complete submillimeter data for the Canada-UK Deep Submillimeter Survey (CUDSS) 3h field. The observations were taken with the Submillimeter Common-User Bolometric Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT) on Mauna Kea. The 3h field is one of two main fields in our survey and covers 60 arcmin
Anomalous Ultraviolet Line Flux Ratios in the Cataclysmic Variables 1RXS J232953.9+062814, CE 315, BZ Ursae Majoris, and EY Cygni, Observed with the Hubble Space Telescope Space Telescope Imaging Spectrograph
Szkody, Paula; Sion, Edward M.; Hubeny, Ivan +6 more
Brief Hubble Space Telescope Space Telescope Imaging Spectrograph spectroscopic snapshot exposures of the cataclysmic variables 1RXS J232953.9+062814, CE 315, BZ UMa, and EY Cyg reveal very large N V/C IV line flux ratios, similar to those observed in AE Aqr. Such anomalous line flux ratios have so far been observed in 10 systems and presumably re…
The DEEP Groth Strip Survey. VII. The Metallicity of Field Galaxies at 0.26 < z < 0.82 and the Evolution of the Luminosity-Metallicity Relation
Kobulnicky, Henry A.; Weiner, Benjamin J.; Faber, S. M. +6 more
Using spectroscopic data from the Deep Extragalactic Evolutionary Probe Groth Strip Survey (DGSS), we analyze the gas-phase oxygen abundances in the warm ionized medium for 64 emission-line field galaxies in the redshift range 0.26<z<0.82. These galaxies comprise a small subset selected from among 693 objects in the DGSS. They are chosen for…
The Nature of Damped Lyα Absorbing Galaxies at z <= 1: A Photometric Redshift Survey of Damped Lyα Absorbers
Chen, Hsiao-Wen; Lanzetta, Kenneth M.
We study the nature of damped Lyα absorption (DLA) systems at z<=1 using a sample of 11 DLA galaxies, for which accurate redshift measurements are available. Five of the 11 systems are identified in our ongoing photometric redshift survey of DLA galaxies, while the remaining six systems are identified by previous groups using either spectroscop…
CO (J=7-->6) Observations of NGC 253: Cosmic-Ray-heated Warm Molecular Gas
Bolatto, A. D.; Stacey, G. J.; Bradford, C. M. +5 more
We report observations of the CO J=7-->6 transition toward the starburst nucleus of NGC 253. This is the highest excitation CO measurement in this source to date and allows an estimate of the molecular gas excitation conditions. Comparison of the CO line intensities with a large velocity gradient, escape probability model indicates that the bul…
Flaring X-Ray Emission from HST-1, a Knot in the M87 Jet
Sparks, W. B.; Wilson, A. S.; Harris, D. E. +3 more
We present Chandra X-ray monitoring of the M87 jet in 2002, which shows that the intensity of HST-1, an optical knot 0.8" from the core, increased by a factor of 2 in 116 days and a factor of 4 in 2 yr. There was also a significant flux decrease over 2 months, with suggestive evidence for a softening of the spectrum. From this variability behavior…
Study of Ribbon Separation of a Flare Associated with a Quiescent Filament Eruption
Zhang, Hongqi; Qiu, Jiong; Jing, Ju +1 more
In this paper, we present a detailed study of a two-ribbon flare in the plage region observed by Kanzelhohe Solar Observatory (KSO), which is one of the stations in our global Hα network. We select this event due to its very clear filament eruption, two-ribbon separation, and association with a fast coronal mass ejection (CME). We study the separa…