Search Publications
The mass function of M 4 from near IR and optical HST observations
Paresce, Francesco; de Marchi, Guido; Pulone, Luigi
Deep images of the galactic globular cluster M 4 taken at various locations with the NIC 3 and the WFPC 2 cameras on HST were used to derive detailed local optical and near IR luminosity functions. White dwarfs have been detected for the first time on a color sequence at constant luminosity in the F110W band. Transformation of the observed luminos…
GHRS Observations of Cool, Low-Gravity Stars. V. The Outer Atmosphere and Wind of the Nearby K Supergiant λ Velorum
Harper, Graham M.; Bennett, Philip D.; Brown, Alexander +3 more
UV spectra of λ Velorum taken with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope are used to probe the structure of the outer atmospheric layers and wind and to estimate the mass-loss rate from this K5 Ib-II supergiant. VLA radio observations at λ=3.6 cm are used to obtain an independent check on the wind velocity a…
Stellar Kinematics of the Double Nucleus of M31
King, Ivan R.; Statler, Thomas S.; Crane, Philippe +1 more
We report observations of the double nucleus of M31 with the f/48 long-slit spectrograph of the Hubble Space Telescope Faint Object Camera. We obtain a total exposure of 19,000 s over seven orbits, with the 0.063"-wide slit along the line between the two brightness peaks (P.A. 42 deg). Careful correction of the raw data for detector backgrounds an…
A classical approach to faint extragalactic source extraction from ISOCAM deep surveys. Application to the Hubble Deep Field
Abergel, A.; Bernard, J. -P.; Clements, D. L. +4 more
We have developed a general data reduction technique for ISOCAM data coming from various deep surveys of faint galaxies. In order to reach the fundamental limits of the camera (due to the background photon noise and the readout noise), we have devised several steps in the reduction processes that transform the raw data to a sky map which is then u…
The Taylor-Proudman Balance and the Solar Rotational Data
Durney, Bernard R.
For the Sun (and because of the presence of buoyancy), the implications of the Taylor-Proudman balance (TPB, a balance between the pressure, Coriolis, and buoyancy forces in the radial and latitudinal momentum equations) differ fundamentally from those of an incompressible fluid. The TPB now only determines the latitudinal variations of the solar …
Mapping the Variegated Surface of Pluto
Buie, Marc W.; Tholen, David J.; Young, Eliot F. +2 more
During the period from 1985 through 1990, Pluto and its satellite Charon underwent a series of transits, eclipses, and occultations, which are collectively called ``mutual events.'' The albedo distribution of Pluto's sub-Charon hemisphere can be determined from these events with a spatial resolution that surpasses any current direct-imaging scheme…
TheUlysses Supplement to the BATSE 4BR Catalog of Cosmic Gamma-Ray Bursts
Cline, T.; Hurley, K.; Kouveliotou, C. +5 more
We present Interplanetary Network localization information for 147 gamma-ray bursts observed by the Burst and Transient Source Experiment between the end of the Third BATSE catalog and the end of the Fourth BATSE catalog, obtained by analyzing the arrival times of these bursts at the Ulysses and Compton Gamma-Ray Observatory (CGRO) spacecraft. For…
Determining the Galactic Mass Distribution Using Tidal Streams from Globular Clusters
Murali, Chigurupati; Dubinski, John
We discuss how to use tidal streams from globular clusters to measure the mass distribution of the Milky Way. Recent proper-motion determinations for globular clusters from plate measurements and Hipparcos astrometry provide several good candidates for Galactic mass determinations in the intermediate halo far above the Galactic disk, including Pal…
Solar wind electrons: Parametric constraints
Goldstein, Bruce E.; Gary, S. Peter; Skoug, Ruth M. +1 more
Solar wind electrons are often observed to consist of two distinguishable components, a thermal, more dense core and a suprathermal, less dense halo. In this core/halo model linear Vlasov theory for the whistler heat flux instability predicts dimensionless heat flux thresholds which decrease as the electron core beta, β~∥c, increases. I…
The three-dimensional solar wind at solar activity minimum
Neugebauer, M.
In early 1998 the Ulysses spacecraft made history by completing an orbit around the Sun inclined to the solar equator by 80°. It observed the properties of the high-latitude heliosphere at a time of low solar activity when the configuration of the solar magnetic field was relatively simple. The solar wind data acquired by Ulysses have placed firm …