Search Publications
First ISOCAM images of the Milky Way.
Elbaz, D.; Prusti, T.; Cesarsky, C. +21 more
ISOGAL is a 15µm ISOCAM survey of ~12deg^2^ in the Galactic Plane interior to |l|=45°. In combination with IJK data from the near-infrared southern sky survey DENIS, the ISO images allow the first detailed study of stellar populations throughout the inner Galaxy. We present preliminary results from a test observation at l= -45° with 6" pixel…
SWS observations of young main-sequence stars with dusty circumstellar disks.
Heras, A. M.; Waters, L. B. F. M.; Beintema, D. A. +18 more
We present SWS full-scan observations of three objects that are thought to be in a stage of evolution between the youngest, embedded, Herbig Ae/Be stars and Beta Pictoris, a young main-sequence star with a circumstellar disk. The 8-12µm spectra of all three stars cannot be understood in terms of purely amorphous silicates, but require the pr…
Optical Rotation Curves of Distant Field Galaxies: Keck Results at Reshifts to Z approximately 1
Illingworth, Garth D.; Forbes, Duncan A.; Faber, S. M. +4 more
Spatially resolved velocity profiles are presented for nine faint field galaxies in the redshift range 0.1 <~ z <~ 1, based on moderate-resolution spectroscopy obtained with the Keck 10 m telescope. These data were augmented with high-resolution Hubble Space Telescope images from WFPC2, which provided V and I photometry, galaxy type, orienta…
Rapid Variability in S5 0716+714 Across the Electromagnetic Spectrum
Quirrenbach, A.; Wagner, S. J.; Zensus, J. A. +14 more
We have investigated the rapid variations of the BL Lac object S5 0716+714 in the radio, optical, ultraviolet, and x-ray regimes. Several simultaneous multifrequency campaigns have been carried out. Here we describe the complete analysis of a four-week monitoring campaign at three radio and three optical frequency bands, simultaneous optical-UV an…
Star-forming galaxies at very high redshifts
Lanzetta, Kenneth M.; Yahil, Amos; Fernández-Soto, Alberto
Analysis of the deepest available images of the sky, obtained by the Hubble Space Telescope, reveals a large number of candidate high-redshift galaxies. A catalogue of 1,683 objects is presented, with estimated redshifts ranging from z = 0 to z > 6. The high-redshift objects are interpreted as regions of star formation associated with the proge…
Triaxial Galaxies with Cusps
Merritt, David; Fridman, Tema
We have constructed fully self-consistent models of triaxial galaxies with central density cusps. The triaxial generalizations of Dehnen's spherical mass models are presented, which have densities that vary as r^-γ^ near the center and r^-4^ at large radii. We computed libraries of ~7000 orbits in each of two triaxial models with γ = 1 ("weak cusp…
A Database for Galaxy Evolution Modeling
Walborn, Nolan R.; Parker, Joel Wm.; Robert, Carmelle +77 more
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of the spectra and evolution of galaxies. A broad variety of empirical and theoretical data are discussed here, and the data are made fully available in the AAS CD-ROM Series, Vo. 7. Several empirical stellar libraries are part of th…
Titan's Surface, Revealed by HST Imaging
Lorenz, R. D.; Sromovsky, L. A.; Caldwell, J. J. +3 more
We present for the first time relative albedo maps of Titan's surface. The maps were made from images taken by the Hubble Space Telescope's planetary camera (295 km per pixel) through atmospheric windows at 940 and 1080 nm. Coverage at all longitudes and between 45°S and 60°N was obtained with 14 orbits from 4-18 October 1994. Each image is charac…
X-ray properties of active galactic nuclei with optical FeII emission.
Wang, T.; Brinkmann, W.; Bergeron, J.
ROSAT spectra of 86 Active Galactic Nuclei (AGN) with a broad range of optical FeII strengths have been analyzed. The results of the spectral analysis have been combined with optical and radio data as well as with optical emission line properties collected from the literature to understand the origin of the strong FeII emission and the nature of t…
The Extragalactic Distance Scale Key Project. IV. The Discovery of Cepheids and a New Distance to M100 Using the Hubble Space Telescope
Illingworth, Garth D.; Madore, Barry F.; Freedman, Wendy L. +19 more
We report on observations of Cepheids in the Virgo spiral galaxy M100, based on data obtained with the Wide Field and Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope (HST). The observations are part of the HST Key Project on the Extragalactic Distance Scale, which aims to provide a measurement of the Hubble constant H_0_ with 10% ac…