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Multicolor Observations of the Hubble Deep Field South
Fontana, Adriano; Grazian, Andrea; Bianchi, Simone +6 more
We present a deep multicolor (U, B, V, I, Js, H, Ks) catalog of galaxies in the Hubble Deep Field South, based on observations obtained with the HST WFPC2 in 1998 and VLT-ISAAC in 1999. The photometric procedures were tuned to derive a catalog optimized for the estimation of photometric redshifts. In particular we adopted a ``conservative'' detect…
Compact Star Clusters in M81. I. Data from Hubble Space Telescope Wide Field Planetary Camera 2 Imaging
Chandar, Rupali; Ford, Holland C.; Tsvetanov, Zlatan
In this paper, we present the discovery of 114 compact star clusters in the nearby spiral galaxy M81 from B-, V-, and I-band Hubble Space Telescope Wide Field Planetary Camera 2 imaging in eight fields, covering a total area of ~40 arcmin2. The fields sample a variety of environments (both spiral and interarm regions), as well as a rang…
Spatially Resolved STIS Spectra of WR+OB Binaries with Colliding Winds
Moffat, Anthony F. J.; Lépine, Sébastien; Shara, Michael M. +2 more
We present spatially resolved spectra of the visual WR+OB massive binaries WR 86, WR 146, and WR 147, obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The systems are classified as follows: WR 86=WC 7+B0 III, WR 146=WC 6+O8 I-IIf, WR 147=WN 8+O5-7 I-II(f). Both WR 146 and WR 147 are known to have strong n…
Sr II and [Sr II] Emission in the Ejecta of η Carinae
Gull, Theodore R.; Hartman, Henrik; Davidson, Kris +3 more
We have discovered four extremely surprising emission lines of strontium in ejecta near η Carinae. Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) observations made in 1999 show two narrow features whose wavelengths correspond to the forbidden transitions of Sr II, and we have found no other plausible identification for th…
A G1-like Globular Cluster in NGC 1023
Larsen, Søren S.
The structure of a very bright (MV=-10.9) globular cluster in NGC 1023 is analyzed on two sets of images taken with the Hubble Space Telescope. From careful modeling of King profile fits to the cluster image, a core radius of rc=0.55+/-0.1 pc, effective radius Re=3.7+/-0.3 pc, and a central surface brightness of &m…
Hubble Space Telescope STIS Observations of the Wolf-Rayet Star HD 5980 in the Small Magellanic Cloud. II. The Interstellar Medium Components
Walborn, Nolan R.; Morrell, Nidia; Tsvetanov, Zlatan +6 more
Observations of the interstellar and circumstellar absorption components obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) along the line of sight toward the Wolf-Rayet-luminous blue variable (LBV) system HD 5980 in the Small Magellanic Cloud are analyzed. Velocity components from C I, C I*, C II, C II*, C IV, N …
New Proplyds, Outflows, Shocks, and a Reflection Nebula in M43 and the Outer Parts of the Orion Nebula
O'Dell, C. R.
Hubble Space Telescope WFPC2 images made as planned parallel observations have produced emission-line images of fields in the outer portions of the Orion Nebula and near the center of the companion H II region, M43. Examination of these images have uncovered three new bright proplyds and one silhouette proplyd. Two of the bright proplyds lie withi…
Orientation and Speed of the Parsec-Scale Jet in NGC 4261 (3C 270)
Jones, Dayton L.; Wehrle, Ann E.; Piner, B. Glenn
NGC 4261 (3C 270) is an elliptical galaxy containing a 300 pc-scale nuclear disk of gas and dust imaged by the Hubble Space Telescope (HST), around a central supermassive black hole. Previous VLBI observations of NGC 4261 revealed a gap in emission in the radio counterjet, presumably due to free-free absorption in the inner parsec of the accretion…
Proper Motion and Excitation Structure of the Expanding Ionized Rings around RY Scuti
Smith, Nathan; Gehrz, Robert D.; Goss, W. M.
Multiepoch HST/WFPC2 images of the massive eclipsing binary RY Scuti reveal that the compact ionized rings in its circumstellar nebula are expanding. Radio images of the free-free continuum at 15 GHz obtained with the Very Large Array confirm the expansion rate and extend the temporal baseline. Combined Hα and radio proper-motion measurements of t…
The Tolman Surface Brightness Test for the Reality of the Expansion. I. Calibration of the Necessary Local Parameters
Sandage, Allan; Lubin, Lori M.
The extensive CCD photometry by Postman & Lauer in the Cape/Cousins R photometric band for first-ranked cluster elliptical and S0 galaxies in 118 low redshift (<z>=0.037) clusters is analyzed for the correlations between average surface brightness, linear radius, and absolute magnitude. The purpose is to calibrate the correlations betwee…