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Hubble Space Telescope Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448
Bond, Howard E.; Panagia, Nino; Balick, Bruce +3 more
We have combined two epochs of Hubble Space Telescope WFPC2 imaging data with ground-based expansion velocities to determine distances to three planetary nebulae (NGC 6578, NGC 6884, and IC 2448). We used two variants of the expansion parallax technique-a gradient method and a magnification method-to determine the distances. The results from the t…
The Apparent Host Galaxy of PKS 1413+135: Hubble Space Telescope, ASCA, and Very Long Baseline Array Observations
Perlman, Eric S.; Stocke, John T.; Sugiho, Masahiko +5 more
PKS 1413+135 (z=0.24671) is one of very few radio-loud active galactic nuclei (AGNs) with an apparent spiral host galaxy. Previous authors have attributed its nearly exponential infrared cutoff to heavy absorption but have been unable to place tight limits on the absorber or its location in the optical galaxy. In addition, doubts remain about the …
ISO LWS Observations of the Two Nearby Spiral Galaxies NGC 6946 and NGC 1313
Dale, Daniel A.; Rubio, Monica; Rubin, Robert H. +8 more
We present the analysis of Infrared Space Observatory long-wavelength spectrometer (LWS) observations of the two nearby late-type galaxies NGC 1313 and NGC 6946. Both galaxies have been fully mapped in the [C II] far-infrared fine-structure line at 158 µm, and some regions have been observed also in the [O I] 63 µm and [N II] 122 &micr…
M-Type Vega-like Stars
Zuckerman, B.; Song, Inseok; Becklin, E. E. +2 more
We carried out a search for M-type Vega-like stars by correlating the IRAS Faint Source Catalog with Hipparcos-selected M-type stars. Three stars with apparent IRAS 25 µm excess emission are shown instead to be non-IR-excess stars from ground-based 11.7 and 17.9 µm photometry. Two stars previously suggested to have Vega-like mid-IR exc…
PMN J1632-0033: A New Gravitationally Lensed Quasar
Winn, Joshua N.; Kochanek, Christopher S.; Morgan, Nicholas D. +6 more
We report the discovery of a gravitationally lensed quasar resulting from our survey for lenses in the southern sky. Radio images of J1632-0033 with the Very Large Array and the Australia Telescope Compact Array exhibit two compact, flat-spectrum components with separation 1.47" and flux density ratio 13.2. Images with the Hubble Space Telescope r…
Imaging of z~2 QSO Host Galaxies with the Hubble Space Telescope
Hutchings, J. B.; Mo, J.; Neff, S. G. +4 more
We report on deep imaging in two filters with the planetary camera of the Hubble Space Telescope of five QSOs at redshift of ~2, with a range of optical and radio luminosity. The observations included a suite of point-spread function (PSF) observations that were used to construct new PSF models, described elsewhere by Dumont et al. The new PSF mod…
Accurate Stellar Population Studies from Multiband Photometric Observations
Kirshner, Robert P.; Panagia, Nino; Romaniello, Martino +1 more
We present a new technique based on multiband near-ultraviolet and optical photometry to measure both the stellar intrinsic properties, i.e., luminosity and effective temperature, and the interstellar dust extinction along the line of sight to hundreds of stars per square arcminute. The yield is twofold. On the one hand, the resulting reddening ma…
Keck Spectroscopy of Young and Old Star Clusters in NGC 1023
Brodie, Jean P.; Larsen, Søren S.
We present Keck/LRIS spectra for 11 old globular clusters in the S0-type galaxy NGC 1023 and two young blue clusters in the nearby companion NGC 1023A. Analysis of the spectra of seven old clusters with sufficient signal-to-noise ratio shows generally good agreement between spectroscopic and previous photometric metallicity estimates, but the inte…
Near-Infrared Adaptive Optics Imaging of the Central Regions of Nearby Sc Galaxies. II. NGC 247 and NGC 2403
Davidge, T. J.; Courteau, S.
J, H, and K' images obtained with the Canada-France-Hawaii Telescope adaptive optics system are used to investigate the star-forming histories of the central regions of the Sc galaxies NGC 247 and NGC 2403. The brightest resolved red stars within 15" of the nucleus of each galaxy are red supergiants (RSGs), indicating that the central few hundred …
Gas Kinematics and the Black Hole Mass at the Center of the Radio Galaxy NGC 4335
Baum, Stefi A.; van der Marel, Roeland P.; de Zeeuw, P. Tim +2 more
We investigate the kinematics of the central gas disk of the radio-loud elliptical galaxy NGC 4335, derived from Hubble Space Telescope (HST) long-slit spectroscopic observations of Hα+[N II] along three parallel slit positions. The observed mean velocities are consistent with a rotating thin disk. We model the gas disk in the customary way, takin…