Search Publications
The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
Dehnen, Walter
Hydrodynamic modeling of the inner Galaxy suggests that the radius of the outer Lindblad resonance (OLR) of the Galactic bar lies in the vicinity of the Sun. How does this resonance affect the distribution function in the outer parts of a barred disk, and can we identify any effect of the resonance in the velocity distribution actually observed in…
Abundances and Kinematics of Field Halo and Disk Stars. I. Observational Data and Abundance Analysis
Fulbright, Jon P.
We describe observations and abundance analysis of a high-resolution, high signal-to-noise ratio survey of 168 stars, most of which are metal-poor dwarfs. We follow a self-consistent LTE analysis technique to determine the stellar parameters and abundances, and we estimate the effects of random and systematic uncertainties on the resulting abundan…
NICMOS Imaging of Infrared-Luminous Galaxies
Surace, J. A.; Armus, L.; Scoville, N. Z. +6 more
We present near-infrared images obtained with the Hubble Space Telescope NICMOS camera for a sample of nine luminous [LIGs: LIR(8-1000 µm)>=1011 Lsolar] and 15 ultraluminous (ULIGS: LIR>=1012 Lsolar) infrared galaxies. The sample includes representative systems classifie…
Disks, Microjets, Windblown Bubbles, and Outflows in the Orion Nebula
O'Dell, C. R.; Bally, John; McCaughrean, Mark J.
New deep narrowband images of the Orion Nebula obtained with WFPC2 on the Hubble Space Telescope (HST) and spectra taken with the HIRES spectrometer at the Keck Observatory are presented. We report eight new circumstellar disks seen in silhouette against the background nebular light and about 30 dark disks embedded within the bright proplyds rimme…
Mapping the Evolution of High-Redshift Dusty Galaxies with Submillimeter Observations of a Radio-selected Sample
Barger, A. J.; Cowie, L. L.; Richards, E. A.
Direct submillimeter imaging has recently revealed the 850 µm background to be mostly composed of a population of distant ultraluminous infrared galaxies, but identifying the optical/near-infrared (NIR) counterparts to these sources has proved difficult because of the poor submillimeter spatial resolution. However, the proportionality of bot…
WFPC2 Observations of the Hubble Deep Field South
Dickinson, Mark; Ferguson, Henry C.; Lucas, Ray A. +14 more
The Hubble Deep Field South (HDF-S) observations targeted a high Galactic latitude field near QSO J2233-606. We present Wide Field Planetary Camera 2 observations of the field in four wide bandpasses centered at roughly 300, 450, 606, and 814 nm. Observations, data reduction procedures, and noise properties of the final images are discussed in det…
Axisymmetric, Three-Integral Models of Galaxies: A Massive Black Hole in NGC 3379
Gebhardt, Karl; Richstone, Douglas; Kormendy, John +8 more
We fit axisymmetric three-integral dynamical models to NGC 3379 using the line-of-sight velocity distribution obtained from Hubble Space Telescope FOS spectra of the galaxy center and ground-based long-slit spectroscopy along four position angles, with the light distribution constrained by WFPC2 and ground-based images. We have fitted models with …
A Search for Environmental Effects on Type IA Supernovae
Phillips, M. M.; Suntzeff, Nicholas B.; Hamuy, Mario +4 more
We use integrated colors and B and V absolute magnitudes of Type Ia supernova (SN) host galaxies in order to search for environmental effects on the SN optical properties. With the new sample of 44 SNe we confirm the conclusion by Hamuy et al. that bright events occur preferentially in young stellar environments. We find also that the brightest SN…
Optical Imaging of Nova Shells and the Maximum Magnitude-Rate of Decline Relationship
Downes, Ronald A.; Duerbeck, Hilmar W.
An optical imaging study of 30 recent novae has been undertaken using both ground-based and space-based observations. Resolved shells have been detected around nine objects in the ground-based data, while another four objects have shells detected by Hubble Space Telescope observations; for RW UMi, we fail to detect a shell that was observed 5 year…
Kinematics of Metal-poor Stars in the Galaxy. II. Proper Motions for a Large Nonkinematically Selected Sample
Beers, Timothy C.; Rossi, Silvia; Platais, Imants +4 more
We present a revised catalog of 2106 Galactic stars, selected without kinematic bias and with available radial velocities, distance estimates, and metal abundances in the range -4.0<=[Fe/H]<=0.0. This update of the 1995 Beers & Sommer-Larsen catalog includes newly derived homogeneous photometric distance estimates, revised radial velocit…