Search Publications
Modeling the distribution of magnetic fluxes in field concentrations in a solar active region
Shine, Richard A.; Title, Alan M.; Schrijver, Carolus J. +1 more
Much of the magnetic field in solar and stellar photospheres is arranged into clusters of `flux tubes', i.e., clustered into compact areas in which the intrinsic field strength is approximately a kilogauss. The flux concentrations are constantly evolving as they merge with or annihilate against other concentrations, or fragment into smaller concen…
Observations of the Hubble Deep Field with the Infrared Space Observatory - II. Source detection and photometry
Elbaz, D.; Danese, L.; Franceschini, A. +18 more
We present positions and fluxes of point sources found in the Infrared Space Observatory (ISO) images of the Hubble Deep Field (HDF) at 6.7 and 15 mu. We have constructed algorithmically selected `complete' flux-limited samples of 19 sources in the 15-mu image, and seven sources in the 6.7-mu image. The typical flux limit at 15 mu is ~0.2 mJy and …
Rings and Satellites of Uranus: Colorful and Not So Dark
Karkoschka, Erich
Photometric properties of nine uranian satellites and four rings, based on six Hubble Space Telescope images taken in 1995, are presented. Derived albedos are consistent with previous data taken at the same phase angle of 1°, but inconsistent with most Voyager-based estimates extrapolated from observations at phase angles above 15°. The shape of p…
The Digital Wave-Processing Experiment on Cluster
Woolliscroft, L. J. C.; Alleyne, H. St. C.; Dunford, C. M. +7 more
Hubble Space Telescope Beryllium Abundances in the α Centauri System
Pinsonneault, M. H.; Deliyannis, Constantine P.; Primas, F. +2 more
High signal-to-noise ratio Hubble Space Telescope Goddard High-Resolution Spectrograph spectra of α Centauri A (spectral type G2 V) and α Centauri B (spectral type K1 V) have been analyzed in the Be II λ3130 spectral region. Both stars offer an excellent opportunity for testing predictions of 9Be destruction since they are nearby, have …
Observations of the SW Sextantis Star BH Lyncis in a High State
Szkody, Paula; Hoard, D. W.
We present time-resolved photometry and medium resolution (2 Å) spectroscopy of the SW Sextantis star BH Lyncis obtained during a high state of the system. Previous detailed observations have been obtained only during low and intermediate states. In addition, we present the first International Ultraviolet Explorer low-resolution (6 Å) spectrum of …
Red giants in the halo of the S0 galaxy NGC 3115: a distance and a bimodal metallicity distribution
Elson, Rebecca A. W.
Using the Hubble Space Telescope, we resolve the red giant branch in the halo of the S0 galaxy NGC 3115. We measure magnitudes and (V-I) colours for stars down to 1.5mag below the tip of the red giant branch. From the brightest stars we estimate a distance modulus (m-M)_0=30.21+/-0.30, corresponding to a distance of 11.0+/-1.5Mpc. This is in excel…
HST Observations of Host Galaxies in Three Radio-selected BL Lacertae Objects
Giavalisco, Mauro; Urry, C. Megan; Scarpa, Riccardo +3 more
We present high-resolution images of three BL Lac objects (0814+425, 1823+568, 2254+074) taken with the WFPC-2 camera on Hubble Space Telescope (HST) as part of a study of BL Lacs from a complete radio-selected sample. In two cases we clearly detect the host galaxies while the third BL Lac (0814+425) is unresolved. The host galaxy of 2254+074 is a…
Active Spacecraft Potential Control
Goldstein, R.; Schmidt, R.; Pedersen, A. +13 more
Barium stars, galactic populations and evolution.
Luri, X.; Figueras, F.; Torra, J. +4 more
In this paper HIPPARCOS astrometric and kinematical data together with radial velocities from other sources are used to calibrate both luminosity and kinematics parameters of Ba stars and to classify them. We confirm the results of our previous paper (where we used data from the HIPPARCOS Input Catalogue), and show that Ba stars are an inhomogeneo…