Search Publications
Spectrophotometry of Four Kuiper Belt Objects with NICMOS
Gilmore, Diane; Noll, Keith S.; Luu, Jane
We have obtained spectrophotometric observations of four Kuiper Belt objects using the Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer, NICMOS, in broad and medium bandwidth filters selected to search for the presence of strong solid state spectral features in the 1.6-2.2 µm range. We find distinct differences in …
The Etched Hourglass Nebula MYCN 18. II. A Spatio-kinematic Model
Trauger, John T.; Gallagher, John S., III; Dayal, Aditya +4 more
We have observed MyCn18, a young planetary nebula, with Hubble Space Telescope/Wide Field Planetary Camera 2 and have presented the observational results in an earlier paper. Here we present a detailed spatio-kinematic model of Hα emission from the nebula. We model the hourglass-shaped nebular lobes as thin-walled structures in the shape of modifi…
The Orbit of the Classical Cepheid AW Persei Revisited
Evans, Nancy Remage; Wahlgren, Glenn M.; Vinko, Jozsef
We have obtained new velocity data for the classical Cepheid AW Persei and used them to derive a new orbit for the binary star system of which it is part. The orbital period (40 yr) is slightly longer than the previously determined orbit. The lower limit to the mass of the secondary from the new mass function is 6.6 Msolar. This is much…
Photometric Redshifts and Morphologies of Galaxies in the NICMOS Parallel Fields
Schneider, Glenn; Rieke, Marcia J.; Vacca, William D. +3 more
We present positions, magnitudes, sizes, and morphological classifications for 111 galaxies discovered in the Hubble Space Telescope NICMOS camera 1 and camera 2 parallel fields. We combine the magnitudes measured in the JHK-analog filters with those from deep ground-based images in V and/or R to measure photometric redshifts for 71 objects using …
Complex Extended Line Emission in the CD Galaxy in Abell 2390
Balogh, M. L.; Hutchings, J. B.
This paper reports maps of the cD galaxy in the rich z=0.23 cluster Abell 2390 at UV, [O II], Lyα, and Hα wavelengths. Spatially resolved UV and optical spectra were obtained with Space Telescope Imaging Spectrograph on the Hubble Space Telescope; the 2" wide slit was aligned close to the long axis and blue lane of the galaxy and includes all the …
Optical Positions for a Sample of ICRF Sources
Assafin, M.; Andrei, A. H.; Martins, R. Vieira +1 more
The aim of this paper is to present a large, coherent set of astrometric optical positions for ICRF sources in the Hipparcos reference frame. For this, we present positions for 315 ICRF sources measured in Digitized Sky Survey (DSS) images, with positions referred to the ACT, Hipparcos, and Tycho catalogs. The reductions were made relative to Hubb…
Comparing Tycho-2 Astrometry with UCAC1
Zacharias, N.; Urban, S. E.; Zacharias, M. I. +1 more
The Tycho-2 Catalogue, released in February 2000, is based on the ESA Hipparcos space mission data and various ground-based catalogs for proper motions. An external comparison of the Tycho-2 astrometry is presented here using the first US Naval Observatory CCD Astrograph Catalog (UCAC1). The UCAC1 data were obtained from observations performed at …
Double Stars in the Tycho-2 Catalogue
Mason, Brian D.; Makarov, Valeri V.; Wycoff, Gary L. +3 more
The Tycho-2 Catalogue provides astrometric and photometric information for 2.5 million stars. Within the Tycho-2 Catalogue, while there is no separate listing of double-star parameters, there is a wealth of double-star data. For all measured double-star systems, each component has its own entry in Tycho-2 (this corresponds to the Hipparcos ``doubl…
Markarian 421'S Unusual Satellite Galaxy
van Zee, Liese; Gorham, Peter W.; Unwin, Stephen C. +1 more
We present Hubble Space Telescope (HST) imagery and photometry of the active galaxy Markarian 421 and its companion galaxy 14" to the east-northeast. The HST images indicate that the companion is a morphological spiral rather than elliptical, as previous ground-based imaging has concluded. The companion has a bright, compact nucleus, appearing unr…
3 Micron Imaging of the Hubble Deep Field
Dickinson, Mark; Djorgovski, S. G.; Hogg, David W. +4 more
Images of the Hubble Deep Field (HDF) at 3.2 µm, taken with the 10 m Keck Telescope, are presented. The images cover a total area of ~2.5 arcmin2. To a 5 σ limit of [3.2]tot~17.5 mag (Vega relative), 11 sources are detected, nine of which are extragalactic. The integrated galaxy number counts are therefore ~1.3x104…