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The ACS Virgo Cluster Survey. VI. Isophotal Analysis and the Structure of Early-Type Galaxies
Jordán, Andrés; Tonry, John L.; Côté, Patrick +8 more
We present a detailed analysis of the morphology, isophotal parameters, and surface brightness profiles for 100 early-type members of the Virgo Cluster, from dwarfs (MB=-15.1 mag) to giants (MB=-21.8 mag), imaged in the g and z passbands using the Advanced Camera for Surveys on board the Hubble Space Telescope. Dust and compl…
The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
Jordán, Andrés; Tonry, John L.; Côté, Patrick +9 more
The ACS Virgo Cluster Survey is a Hubble Space Telescope program to obtain high-resolution imaging in widely separated bandpasses (F475W~g and F850LP~z) for 100 early-type members of the Virgo Cluster, spanning a range of ~460 in blue luminosity. We use this large, homogenous data set to examine the innermost structure of these galaxies and to cha…
Hubble Space Telescope NICMOS Observations of T Dwarfs: Brown Dwarf Multiplicity and New Probes of the L/T Transition
Burrows, Adam; Kirkpatrick, J. Davy; Burgasser, Adam J. +5 more
We present the results of a Hubble Space Telescope NICMOS imaging survey of 22 T-type field brown dwarfs. Five are resolved as binary systems with angular separations of 0.05"-0.35", and companionship is established on the basis of component F110W-F170M colors (indicative of CH4 absorption) and low probabilities of background contaminat…
Cepheid Distances to SNe Ia Host Galaxies Based on a Revised Photometric Zero Point of the HST WFPC2 and New PL Relations and Metallicity Corrections
Saha, A.; Tammann, G. A.; Thim, F. +2 more
With this paper we continue the preparation for a forthcoming summary report of our experiment with the HST to determine the Hubble constant using Type Ia supernovae as standard candles. Two problems are addressed. (1) We examine the need for, and determine the value of, the corrections to the apparent magnitudes of our program Cepheids in the 11 …
Hubble Space Telescope Proper Motions and Stellar Dynamics in the Core of the Globular Cluster 47 Tucanae
Anderson, Jay; Gebhardt, Karl; Minniti, Dante +4 more
We have used HST imaging of the central regions of the globular cluster 47 Tucanae (=NGC 104), taken with the WFPC2 and ACS instruments between 1995 and 2002, to derive proper motions and U- and V-band magnitudes for 14,366 stars within 100" (about 5 core radii) of the cluster center. This represents the largest set of member velocities collected …
Properties of O VI Absorption in the Local Interstellar Medium
Savage, Blair D.; Lehner, Nicolas
The measurement of absorption over short distances in the local interstellar medium (LISM) provides an excellent opportunity to study the properties of O VI absorption and its kinematic relationship to absorption by tracers of cool and warm gas. We report on the properties of LISM O VI absorption observed with 20 km s-1 resolution Far U…
The Local Group Stellar Populations Archive from the Hubble Space Telescope WFPC2
Dolphin, Andrew; Holtzman, Jon A.; Afonso, Cristina
We present a database (LOGPHOT) of stellar photometry of Local Group galaxies obtained with the Hubble Space Telescope using the Wide Field Planetary Camera 2 (WFPC2). The database includes photometry from all WFPC2 observations taken through 2003 with long exposures (>500 s) in F555W and F814W, and many observations in which long exposures wer…
The Origins of Fluorescent H2 Emission From T Tauri Stars
Herczeg, Gregory J.; Walter, Frederick M.; Johns-Krull, Christopher M. +2 more
We survey fluorescent H2 emission in HST STIS spectra of the classical T Tauri stars (CTTSs) TW Hya, DF Tau, RU Lupi, T Tau, and DG Tau, and the weak-lined T Tauri star (WTTS) V836 Tau. From each of those sources we detect between 41 and 209 narrow H2 emission lines, most of which are pumped by strong Lyα emission. H2
A FUSE Survey of High-Latitude Galactic Molecular Hydrogen
Wakker, B. P.
Measurements of molecular hydrogen (H2) column densities are presented for the first six rotational levels (J=0-5) for 73 extragalactic targets observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). All of these have a final signal-to-noise ratio larger than 10 and are located at Galactic latitude |b|>20deg. The …
Hubble Space Telescope Near-Infrared Snapshot Survey of 3CR Radio Source Counterparts at Low Redshift
O'Dea, Christopher P.; Sparks, William B.; Baum, Stefi +9 more
We present newly acquired images of the near-infrared counterpart of 3CR radio sources. All the sources were selected to have a redshift of less than 0.3 to allow us to obtain the highest spatial resolution. The observations were carried out as a snapshot program using the Near-Infrared Camera and Multiobject Spectrograph (NICMOS) on-board the Hub…