Search Publications
Hubble Space Telescope Spectroscopy of the Nucleus of M33
Long, Knox S.; Dubus, Guillaume; Charles, Philip A.
We have used the Hubble Space Telescope to obtain moderate resolution 1150-5700 Å spectroscopy of the nucleus of M33 and a blue star ~1" north-northwest of the nucleus in an attempt to find the optical counterpart of the nuclear X-ray source and to characterize stellar populations in the nuclear region. The Space Telescope Imaging Spectrograph spe…
Tomographic Separation of Composite Spectra. VIII. The Physical Properties of the Massive Compact Binary in the Triple Star System HD 36486 (δ Orionis A)
Gies, Douglas R.; Penny, Laura R.; Bagnuolo, William G., Jr. +2 more
We present the first double-lined spectroscopic orbital elements for the central binary in the massive triple δ Orionis A. The solutions are based on fits of cross-correlation functions of IUE high-dispersion UV spectra and He I λ6678 profiles. The orbital elements for the primary agree well with previous results, and in particular, we confirm the…
Chandra X-Ray Observatory Observation of A1689: New Determination of Mass Distribution and Comparison to Lensing Measurements
Wu, Xiang-Ping; Xue, Sui-Jian
We present a new estimate of the projected X-ray mass of A1689 observed with Chandra X-Ray Observatory, in an attempt to clarify the issue of whether or not there exists a discrepancy between X-ray and gravitational lensing mass estimates claimed in previous investigations based on Einstein, ROSAT, and ASCA observations. Particular attention is pa…
Localizing Width and Energy of Solar Global p-Modes
Howe, R.; Komm, R.; Hill, F.
We present the first attempt at localizing in latitude the temporal variation of mode energy, energy supply rate, and lifetime of global acoustic modes. We use Global Oscillation Network Group (GONG) and Michelson Doppler Imager data analyzed with the GONG peak-fitting algorithm to measure mode width and amplitude of individual (l, n, m) modes. Wh…
Losing Weight: A Keck Spectroscopic Survey of the Massive Cluster of Galaxies RX J1347-1145
Kneib, Jean-Paul; Cohen, Judith G.
We present a sample of 47 spectroscopically confirmed members of RX J1347-1145, the most luminous X-ray cluster of galaxies discovered to date. With two exceptions, all the galaxies in this sample have red B-R colors and red spectral indices, with spectra similar to old local elliptical galaxies. Using all 47 cluster members, we derive a mean reds…
Hubble Space Telescope Space Telescope Imaging Spectrograph Search for an Atmosphere on Callisto: A Jovian Unipolar Inductor
Saur, Joachim; Feldman, Paul D.; Strobel, Darrell F. +1 more
Hubble Space Telescope observations of Callisto with the Space Telescope Imaging Spectrograph were performed at both eastern and western elongations to search for the UV emissions diagnostic of the presence of O2, CO2, and/or CO atmospheres. We report upper limits of 5×10-5 photons cm-2 s-1 or…
Chemical Evolution of the Circumstellar Envelopes of Carbon-rich Post-Asymptotic Giant Branch Objects
Cernicharo, J.; Goicoechea, J. R.; Herpin, F. +1 more
We have observed, with the 30 m IRAM telescope, the Caltech Submillimeter Observatory telescope, and the Infrared Space Observatory (ISO) satellite,3 the rotational lines of CO at millimeter, submillimeter, and far-IR wavelengths in the direction of carbon-rich stellar objects at different stages of evolution: CRL 2688 (a very young proto-planetar…
Resolving the 47 Tucanae Distance Problem
Salaris, Maurizio; Kilkenny, David; van Wyk, Francois +1 more
We present new B-, V-, and I-band photometry for a sample of 43 local subdwarfs with Hipparcos parallax errors less than 13%, in the metallicity range -1.0<[Fe/H]<-0.3, which we use to perform main-sequence (MS) fitting to the Galactic globular cluster 47 Tuc. This sample is many times larger than those used in previous MS-fitting studies an…
High-Resolution X-Ray Spectroscopy of Hercules X-1 with the XMM-Newton Reflection Grating Spectrometer: CNO Element Abundance Measurements and Density Diagnostics of a Photoionized Plasma
Zane, S.; Ramsay, G.; Hailey, C. J. +2 more
We analyze the high-resolution X-ray spectrum of Hercules X-1, an intermediate-mass X-ray binary, which was observed with the XMM-Newton Reflection Grating Spectrometer. We measure the elemental abundance ratios by use of spectral models, and we detect material processed through the CNO cycle. The CNO abundances and, in particular, the ratio N/O&g…
Wide Field Planetary Camera 2 Observations of the Polar Ring Galaxy NGC 4650A
Gallagher, J. S.; Sparke, L. S.; Kinney, A. L. +5 more
We present multicolor Wide Field Planetary Camera 2 images of the polar ring galaxy NGC 4650A (D=35 Mpc), taken with the Hubble Space Telescope. These data allow a detailed examination of the morphology of the central S0 component and the surrounding ``polar ring'' of stars, gas, and dust, which are spatially extended and form a ``polar disk.'' Th…