Search Publications
The Nature of Compact Galaxies in the Hubble Deep Field. I. Global Properties1,
Illingworth, Garth D.; Faber, S. M.; Koo, David C. +5 more
We present 10 m Keck spectroscopy and photometry for a sample of 61 small (r1/2 <= 0.5"), faint (I814 <= 23.74), high-surface brightness (µI814 < 22.2 mag arcsec-2) galaxies in fields flanking the Hubble Deep Field. The majority of this empirically defined sample of compact galaxies lies a…
The Abundance of Interstellar Nitrogen
Sofia, Ulysses J.; Meyer, David M.; Cardelli, Jason A.
Using the Hubble Space Telescope Goddard High Resolution Spectrograph (GHRS), we have obtained high S/N echelle observations of the weak interstellar N I λλ1160, 1161 absorption doublet toward the stars γ Cas, λ Ori, ι Ori, κ Ori, δ Sco, and κ Sco. In combination with a previous GHRS measurement of N I toward ζ Oph, these new observations yield a …
External supply of oxygen to the atmospheres of the giant planets
Lellouch, E.; Encrenaz, T.; de Graauw, T. +3 more
The atmospheres of the giant planets are reducing, being mainly composed of hydrogen, helium and methane. But the rings and icy satellites that surround these planets, together with the flux of interplanetary dust, could act as important sources of oxygen, which would be delivered to the atmospheres mainly in the form of water ice or silicate dust…
A Catalog of Morphological Types in 10 Distant Rich Clusters of Galaxies
Smail, Ian; Ellis, Richard S.; Dressler, Alan +4 more
We present catalogs of objects detected in deep images of 11 fields in 10 distant clusters obtained using WFPC-2 on board the Hubble Space Telescope. The clusters span the redshift range z = 0.37-0.56 and are the subject of a detailed ground- and space-based study to investigate the evolution of galaxies as a function of environment and epoch. The…
A Coronal Spectrum in the 500--1610 Angstrom Wavelength Range Recorded at a Height of 21,000 Kilometers above the West Solar Limb by the SUMER Instrument on Solar and Heliospheric Observatory
Wilhelm, K.; Curdt, W.; Schühle, U. +4 more
We present a solar coronal spectrum recorded by the extreme UV spectrometer SUMER on the Solar and Heliospheric Observatory. The spectrum was taken between 21:28 UT on 1996 June 25 and 02:47 UT on 1996 June 26, at a height of 21,000 km above the west equatorial limb with the slit oriented in the north-south direction. At the time of the observatio…
The HIPPARCOS catalogue as a realisation of the extragalactic reference system
Zacharias, N.; Kozhurina-Platais, V.; Hemenway, P. D. +23 more
The paper describes the methods and observations by which the Hipparcos Catalogue was linked to the International Celestial Reference System (ICRS). The contributions of several groups represented in the authorship of this paper, using a variety of techniques, were synthesised in order to determine the global orientation and rotation (spin) of the…
Cataclysmic variables in the ROSAT PSPC All Sky Survey.
Verbunt, F.; Bunk, W. H.; Ritter, H. +1 more
91 cataclysmic variables from a sample of 162 systems with known or suspected binary periods were detected during the ROSAT XRT-PSPC All Sky Survey. Among the non-magnetic systems, the X-ray to optical/ultraviolet flux ratio decreases along the sequence SU UMa type - U Gem type - Z Cam type - UX UMa type, due mainly to variations in the optical/ul…
Evolution of Early-Type Galaxies in Distant Clusters: The Fundamental Plane from Hubble Space Telescope Imaging and Keck Spectroscopy
van Dokkum, Pieter G.; Franx, Marijn; Kelson, Daniel D. +2 more
We present new results on the fundamental plane of galaxies in two rich clusters, Cl 1358+62 at z = 0.33 and MS 2053-04 at z = 0.58, based on Keck and Hubble Space Telescope observations. Our new data triple the sample of galaxies with measured fundamental plane parameters at intermediate redshift. The early-type galaxies in these clusters define …
EUV Blinkers: The Significance of Variations in the Extreme Ultraviolet Quiet Sun
Harrison, Richard A.
A search for microflare activity in the extreme ultraviolet (EUV) quiet Sun using the Coronal Diagnostic Spectrometer (CDS) aboard the Solar and Heliospheric Observatory (SOHO) spacecraft has not resulted in the identification of microflare activity, but has resulted in the identification of a hitherto unknown phenomenon: enhancements of a factor …
Hubble Space Telescope Faint Object Spectroscope Spectroscopy of Localized Chemical Enrichment from Massive Stars in NGC 5253
Kobulnicky, Henry A.; Skillman, Evan D.; Walsh, J. R. +2 more
Optical and ultraviolet spectroscopy obtained with the Hubble Space Telescope Faint Object Spectrograph at three locations in the central H II complex of the amorphous starburst galaxy NGC 5253 confirms an apparent area of enhanced nitrogen abundance seen in ground-based studies. At two positions, N appears enhanced by a factor of 3 [log (N/O) = -…