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WFPC2 Observations of Star Clusters in the Magellanic Clouds. II. The Oldest Star Clusters in the Small Magellanic Cloud
Sarajedini, Ata; Mighell, Kenneth J.; French, Rica S.
We present our analysis of archival Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) observations in F450W (~B) and F555W (~V) of the intermediate-age populous star clusters NGC 121, NGC 339, NGC 361, NGC 416, and Kron 3 in the Small Magellanic Cloud. We use published photometry of two other SMC populous star clusters, Lindsay 1 and Li…
Keck Spectroscopy and NICMOS Photometry of a Redshift Z = 5.60 Galaxy
Bunker, Andrew; Spinrad, Hyron; Stern, Daniel +4 more
We present Keck Low Resolution Imaging Spectrometer spectroscopy along with Near-Infrared Camera and Multiobject Spectrometer (NICMOS) F110W (~J) and F160W (~H) images of the galaxy HDF 4-473.0 in the Hubble Deep Field (HDF), with a detection of an emission line consistent with Lyα at a redshift of z=5.60. Attention to this object as a high-redshi…
Laboratory identification of the 4.62mu M solid state absorption band in the ISO-SWS spectrum of RAFGL 7009S
Heras, A. M.; Dartois, E.; Demyk, K. +3 more
We focus on the problem of the assignment of the ``XCN'' solid state feature observed in the spectra of numerous protostellar objects. This feature, located at 4.62µm has been tentatively identified with the molecular ion OCN(-) . New laboratory experiments have been performed in order to confirm this identification. OCN(-) is produced by UV…
Helioseismic Measurements of the Subsurface Meridional Flow
Braun, D. C.; Fan, Y.
We measure the mean frequencies of acoustic (p-mode) waves propagating toward and away from the poles of the Sun from observations made with the Solar Oscillations Investigation-Michelson Doppler Imager on board the Solar and Heliospheric Observatory and the ground-based Global Oscillations Network Group. We demonstrate that there is a significant…
Ion Temperatures in a Solar Polar Coronal Hole Observed by SUMER on SOHO
Wilhelm, K.; Tu, C. -Y.; Marsch, E. +1 more
The temperatures of some highly charged ions in the southern solar polar coronal hole are determined from the widths of the extreme ultraviolet (EUV) lines measured by the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument on SOHO (Solar and Heliospheric Observatory). Radiation from both light ions, such as Ne6+, Ne<…
ISO deep far-infrared survey in the ``Lockman Hole''. A search for obscured objects at high redshift. I. Observations
Sanders, D. B.; Kawara, K.; Taniguchi, Y. +11 more
Two 44arcmin x 44arcmin fields in the Lockman Hole were mapped at 95 mu m and 175 mu m using ISOPHOT. A simple program code combined with PIA works well to correct for drift in the detector responsivity. The number density of 175 mu m sources is 3-10 times higher than expected from the no-evolution model. Based on observations with ISO, an ESA pro…
Investigation of the variability of bright Be stars using HIPPARCOS photometry
Floquet, M.; Hubert, A. M.
The high accuracy and the homogeneity of Hipparcos data for bright stars have allowed us to quantify the degree of variability of Be stars. This degree has been found to be highly dependent on the temperature of the star. Rapid variability is the main feature of the 86% of early Be and less than 20% of late Be stars taking into account the limit o…
Wide Field Planetary Camera 2 Observations of Leo A: A Predominantly Young Galaxy within the Local Group
Saha, A.; Gallagher, J. S.; Cole, A. A. +6 more
The unprecedented detail of the Wide Field Planetary Camera 2 (WFPC2) color-magnitude diagrams (CMDs) of the resolved stellar population of Leo A presented here allows us to determine a new distance and an accurate star formation history for this extremely metal-poor Local Group dwarf irregular galaxy. From the position of the red clump, the heliu…
Hubble Space Telescope imaging of Jupiter's UV aurora during the Galileo orbiter mission
Gérard, Jean-Claude; Clarke, John T.; Ben Jaffel, Lotfi
Hubble Space Telescope (HST) Wide-Field Planetary Camera 2 (WFPC 2) images of Jupiter's aurora have been obtained close in time with Galileo ultraviolet spectrometer (UVS) spectra and in situ particles, fields, and plasma wave measurements between June 1996 and July 1997, overlapping Galileo orbits G1, G2, G7, G8, and C9. This paper presents HST i…
Hubble Space Telescope Observations of Neutron-Capture Elements in Very Metal Poor Stars
Truran, James W.; Sneden, Christopher; Cowan, John J. +1 more
Using the Goddard High-Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) we have detected the neutron-capture elements osmium, platinum, and lead in the very metal poor ([Fe/H] ~= -2.8) Galactic halo star HD 115444. This star joins the metal-poor giant HD 126238 ([Fe/H] ~= -1.7) as the second Galactic halo star for which ``third n…