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A Near-Infrared Stellar Census of the Blue Compact Dwarf Galaxy VII ZW 403
Greggio, Laura; Hopp, Ulrich; Schulte-Ladbeck, Regina E. +1 more
We present near-infrared single-star photometry for the low-metallicity blue compact dwarf galaxy VII Zw 403. We achieve limiting magnitudes of F110W~25.5 and F160W~24.5 using one of the NICMOS cameras with the Hubble Space Telescope equivalents of the ground-based J and H filters. The data have a high photometric precision (0.1 mag) and are more …
Ultraviolet Spectral Classification of O and B Stars in the Large Magellanic Cloud
Bruhweiler, Frederick C.; Smith Neubig, Margaret M.
In this extension of our previous ultraviolet classification study of Small Magellanic Cloud stars, we construct an ultraviolet classification system for stars of the Large Magellanic Cloud, a galaxy with a metallicity intermediate to those of the Milky Way and the SMC. Employing the same method as was used for the SMC, we compile a set of LMC spe…
High-Velocity Line Emission in the Narrow-Line Region of NGC 4151
Gull, T. R.; Kraemer, S. B.; Crenshaw, D. M. +6 more
Narrowband imaging of the nuclear region of NGC 4151 with the Hubble Space Telescope is presented. The filter bandpasses isolate line emission in various high-velocity ranges in several ions. Slitless and long-slit spectra of the region with the Space Telescope Imaging Spectrograph also indicate the locations of high-velocity gas. These emission r…
A Large H I Shell surrounding the Wolf-Rayet Star HD 191765
St-Louis, Nicole; Gervais, Simon
We have surveyed a 2.6dx2.6d field centered on the Wolf-Rayet (W-R) star HD 191765 (=WR 134) in the H I 21 cm line and in the 1420 and 408 MHz radio continuum, using the Synthesis Telescope of the Dominion Radio Astrophysical Observatory, to search for direct evidence of the interaction between the W-R star wind and the interstellar medium. An arc…
HUBBLE SPACE TELESCOPE Images of the Compact Nebula around RY Scuti
Smith, Nathan; Gehrz, Robert D.; Humphreys, Roberta M. +3 more
We present HST Wide Field Planetary Camera 2 images of the very massive eclipsing binary RY Scuti. The HST Hα image shows a very complex ionized nebula roughly 1" in size. Several interesting structures are revealed, including what appears to be a pair of concentric ionized rings above and below the equatorial plane of the system, located at the i…
Quasar Candidates in the Hubble Deep Field
Martini, Paul; Conti, Alberto; Kennefick, Julia D. +1 more
The Hubble Deep Field (HDF) gives us an unprecedented view of our universe and an opportunity to study a wide range of questions in galaxy evolution and cosmology. Here we focus on the search for unresolved faint quasars and active galactic nuclei (AGNs) in the crude combine images using a multicolor imaging analysis that has proved very successfu…
CTQ 414: A New Gravitational Lens
Dressler, Alan; Winn, Joshua N.; Morgan, Nicholas D. +2 more
We report the discovery and ground-based observations of the new gravitational lens CTQ 414. The source quasar lies at a redshift of z=1.29 with a B magnitude of 17.6. Ground-based optical imaging reveals two point sources separated by 1.2" with a magnitude difference of roughly 1 mag. Subtraction of two stellar point-spread functions from images …
The Nearby Low-Mass Visual Binary Wolf 424
Torres, Guillermo; Henry, Todd J.; Wasserman, Lawrence H. +1 more
We present new measurements of the relative positions of the components of the low-mass visual binary Wolf 424 (M5.5 Ve) made with the Fine Guidance Sensors on the Hubble Space Telescope. Previous analyses of the astrometric orbit of this system indicated that the components have substellar masses (Heintz; Schultz et al.), raising considerable int…
Investigating the Metal Line Systems at Z=1.9 toward J2233-606 in the Hubble Deep Field South
Prochaska, Jason X.; Burles, Scott M.
The combination of Space Telescope Imaging Spectrograph (STIS) and optical spectroscopy with STIS imaging of the field surrounding J2233-606 affords a unique opportunity to study the physical nature of the quasar absorption-line systems. We present an analysis of the ionization state, chemical abundances, and kinematic characteristics of two metal…
Infrared Photometry of Red Supergiants in Young Clusters in the Magellanic Clouds
Keller, Stefan C.
We present broadband infrared photometry for 52 late-type supergiants in the young Magellanic Cloud clusters NGC 330, 1818, 2004, and 2100. Standard models are seen to differ in the temperature they predict for the red supergiant population by on the order of 300 K. It appears that these differences are most probably due to the calibration of the …