Search Publications
Cl 1358+62: Characterizing the Physical Properties of Cluster Galaxies at z = 0.33
Franx, Marijn; Tran, Kim-Vy H.; Simard, Luc +1 more
We examine the physical properties of 173 cluster members in Cl 1358+62 (z=0.3283) from Hubble Space Telescope Wide Field Planetary Camera 2 imaging taken in the F606W (~rest-frame B) and F814W (~rest-frame V) filters over a 2.2×2.2 Mpc2 field (H0=100 km s-1 Mpc-1, ΩM=0.3, ΩΛ=0.7). …
Accretion and Outflow in Interacting Binary Systems: Far Ultraviolet Spectroscopic Explorer Observations of the Nova-like Cataclysmic Variable UX Ursae Majoris
Long, Knox S.; Froning, Cynthia S.; Knigge, Christian
We present far-ultraviolet (905-1182 Å), time-series spectroscopy of the eclipsing, nova-like cataclysmic variable UX UMa acquired with Far Ultraviolet Spectroscopic Explorer (FUSE). The time-averaged spectrum is complex and is dominated by overlapping spectral features. The most prominent features are emission lines of C III, N III, N IV, and O V…
Hubble Space Telescope Spectroscopy of the Unexpected 2001 July Outburst of the Dwarf Nova WZ Sagittae
Szkody, Paula; Howell, Steve B.; Sion, Edward M. +8 more
We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph E140M spectra of the dwarf nova WZ Sge, following the early superoutburst of 2001 July. Our four far-ultraviolet (FUV) spectra, obtained over a time span of 4 months, monitor changes in the hot component of the system during the decline phase. The spectra cover the wavele…
Helium Abundance in the Corona and Solar Wind: Gyrotropic Modeling from the Chromosphere to 1 AU
Hansteen, Viggo H.; Lie-Svendsen, Øystein; Leer, Egil
We have developed a solar wind model including helium that extends from the chromosphere to 1 AU. The model is based on the gyrotropic approximation to the 16-moment set of fluid transport equations, which allows it to accommodate temperature anisotropies, as well as nonclassical heat transport. We find that, as in a pure electron-proton solar win…
Blue Horizontal-Branch Stars in Old, Metal-rich Stellar Systems
O'Connell, Robert W.; Dorman, Ben; Rood, Robert T. +5 more
Twenty years ago, Burstein et al. recognized that the metal-rich globular clusters in the Andromeda galaxy (M31) exhibited anomalously strong Balmer and CN lines compared to Milky Way clusters. They suggested that younger ages might be the cause, unless blue stars above the main-sequence turnoff or on the horizontal branch were uncommonly prominen…
The Distance to the Large Magellanic Cloud Cluster NGC 1866 and the Surrounding Field
Salaris, M.; Walker, A. R.; Brocato, E. +2 more
We use the main-sequence stars in the LMC cluster NGC 1866 and red clump stars in the local field to obtain two independent estimates of the LMC distance. We apply an empirical main-sequence-fitting technique based on a large sample of subdwarfs with accurate Hipparcos parallaxes in order to estimate the cluster distance modulus, and the multicolo…
The ASCA X-Ray Spectrum of Arp 102B and Evaluation of Simple Models for Its Associated, Metastable Fe II Absorber
Charlton, Jane C.; Eracleous, Michael; Halpern, Jules P.
We have observed the broad-line radio galaxy Arp 102B with ASCA in order to determine the absorbing column density toward its X-ray source and measure its X-ray spectrum. The ultimate goal was to constrain the properties of the medium responsible for the metastable Fe II absorption lines observed in the ultraviolet spectrum of this object. The 0.5…
Nitrogen Overabundance: Globular Cluster and Halo Formation
Burstein, David; Li, Yong
Halo globular clusters pose four succinct issues that must be solved in any scenario of their formation: single-age, single-metallicity stellar populations; a lower limit ([Fe/H]~-2.5) to their average metallicity; comprising only 1% of the stellar halo mass; and being among the oldest stars in our Galaxy. New spectra are presented of Galactic sta…
NGC 2264 IRS 1: The Central Engine and Its Cavity
Stecklum, B.; Henning, Th.; Linz, H. +1 more
We present a high-resolution study of NGC 2264 IRS 1 in CS 2-->1 and in the 3 mm continuum using the IRAM Plateau de Bure interferometer. We complement these radio data with images taken at 2.2, 4.6, and 11.9 µm. The combined information allows a new interpretation of the closest environment of NGC 2264 IRS 1. No disk around the B-type st…
Smaug: A New Technique for the Deprojection of Galaxy Clusters
Molendi, Silvano; Ghizzardi, Simona; De Grandi, Sabrina +1 more
This paper presents a new technique for reconstructing the spatial distributions of hydrogen, temperature, and metal abundance of a galaxy cluster. These quantities are worked out from the X-ray spectrum, modeled starting from few analytical functions describing their spatial distributions. These functions depend on some parameters, determined by …