Search Publications
Star Formation in and Evolution of the Blue Compact Dwarf Galaxy UGC 6456 Determined from Hubble Space Telescope Images
Tolstoy, Eline; Lynds, Roger; O'Neil, Earl J., Jr. +1 more
Photometry on the UVI system has been performed on the resolved stellar content of the blue compact dwarf galaxy UGC 6456 using Wide Field Planetary Camera 2 (WFPC2) images obtained with the Hubble Space Telescope. The resulting color-magnitude diagram (CMD) goes to about V = 27.5 and reveals not only a young population of blue main-sequence stars…
Mid-IR emission of galaxies in the Virgo cluster. II. Integrated properties
Boulanger, F.; Sauvage, M.; Boselli, A. +7 more
We analyse the integrated properties of the Mid-IR emission of a complete, optically selected sample of galaxies in the Virgo cluster observed with the ISOCAM instrument on board the ISO satellite. The ISOCAM data allows us to construct the luminosity distribution at 6.75 and 15 mu m of galaxies for different morphological classes. These data are …
A ``Short'' Distance to the Large Magellanic Cloud With the Hipparcos Calibrated Red Clump Stars
Zaritsky, D.; Stanek, K. Z.; Harris, J.
Following an approach developed by Paczyński & Stanek, we derive a distance to the Large Magellanic Cloud (LMC) by comparing red clump stars from the Hipparcos catalog with the red clump stars observed in two fields in the LMC that were selected from the ongoing photometric survey of the Magellanic Clouds to lie in low-extinction regions. The …
The distribution of nearby stars in phase space mapped by HIPPARCOS. II. Inhomogeneities among A-F type stars
Creze, M.; Chereul, E.; Bienayme, O.
A volume limited and absolute magnitude limited sample of A-F type dwarfs within 125 parsecs of the Sun is searched for inhomogeneities in the density-velocity space, expecting signatures of the cluster evaporation, phase mixing and possible disc heating mechanisms. A 3-D wavelet analysis is used to extract inhomogeneities, both in the density and…
Characteristics of the Galileo probe entry site from Earth-based remote sensing observations
Baines, Kevin H.; Hora, Joseph; Hinkley, Sasha +14 more
A reassessment of ground-based observations confirms to better than a 98% confidence level that the Galileo probe entered a 5-µm hot spot, a region of unusual clarity and dryness, some 900+/-300km north of its southern boundary. Cloud conditions at that point were similar to those in the center of this region, some 600 km further north. At t…
A High-Dispersion Spectroscopic Survey of the Hot White Dwarfs: The IUE NEWSIPS SWP Echelle Data Set
Barstow, M. A.; Sion, E. M.; Holberg, J. B.
This paper summarizes the results obtained from a comprehensive analysis of all of the SWP echelle spectra of the white dwarf stars contained in the IUE Final Archive. A total of 209 NEWSIPS spectra of 55 degenerate stars of various types have been systematically reduced and analyzed. These include, in addition to conventional white dwarfs, severa…
A Study of Nine High-Redshift Clusters of Galaxies. III. Hubble Space Telescope Morphology of Clusters 0023+0423 and 1604+4304
Schneider, Donald P.; Postman, Marc; Hoessel, John G. +4 more
We present a detailed morphological analysis of the galaxy populations in the first two clusters to be completed in an extensive observational study of nine high-redshift clusters of galaxies. These two clusters, Cl 0023+0423 and Cl 1604+4304, are at redshifts of z = 0.84 and z = 0.90, respectively. The morphological studies are based on high angu…
Molecular Gas in the Eagle Nebula
Pound, Marc W.
We present the first images of the molecular gas in the Eagle Nebula. Our maps of 12CO (1-0), 13CO (1-0), and 12C18O (1-0) emission, which have about 10" (~0.1 pc) resolution, reveal a molecular cloud being demolished by the intense activity of nearby O stars. Velocity gradients in the molecular gas reac…
The Ultraviolet Luminosity Density of the Universe from Photometric Redshifts of Galaxies in the Hubble Deep Field
Lanzetta, Kenneth M.; Pascarelle, Sebastian M.; Fernández-Soto, Alberto
Studies of the Hubble Deep Field (HDF) and other deep surveys have revealed an apparent peak in the ultraviolet (UV) luminosity density, and therefore the star formation rate density, of the universe at redshifts 1<z<2. We use photometric redshifts of galaxies in the HDF to determine the comoving UV luminosity density, and we find that, when…
Adiabatic Deceleration of Solar Energetic Particles as Deduced from Monte Carlo Simulations of Interplanetary Transport
Vainio, R.; Torsti, J.; Kocharov, L. +1 more
Monte Carlo simulations of interplanetary transport are employed to study adiabatic energy losses of solar protons during propagation in the interplanetary medium. We consider four models. The first model is based on the diffusion-convection equation. Three other models employ the focused transport approach. In the focused transport models, we sim…