Search Publications
The Evolution of Ultraviolet Emission Lines From Circumstellar Material Surrounding SN 1987A
Cassatella, Angelo; Gilmozzi, Roberto; Fransson, Claes +5 more
The presence of narrow high-temperature emission lines from nitrogen-rich gas close to SN 1987A has been a principal observational constraint on the evolutionary status of the supernova's progenitor. A new analysis of the complete 5 year set of low- and high-resolution IUE ultraviolet spectra of SN 1987A (1987.2-1992.3) provides fluxes for the N V…
SWICS/Ulysses observations: The three-dimensional structure of the heliosphere in the declining/minimum phase of the solar cycle
Livi, S.; Woch, J.; Geiss, J. +5 more
The ESA/NASA spacecraft Ulysses provides the first in-situ observation of the solar wind at high solar latitudes. Data obtained with the Solar Wind Ion Composition Spectrometer (SWICS) during the first orbit of Ulysses around the Sun can be used to obtain a global view of the solar wind pattern within the heliosphere during the declining/minimum p…
HST observations of the field star population in the Large Magellanic Cloud
Elson, Rebecca A. W.; Gilmore, Gerard F.; Santiago, Basilio X.
We present V and I photometry, obtained with the Hubble Space Telescope, for ~15 800 stars in a field in the inner disc of the Large Magellanic Cloud. We confirm previous results indicating that an intense star formation event, probably corresponding to the formation of the LMC disc, occurred a few times 10^9 yr ago. We find a small but real diffe…
Observations and Theoretical Implications of GRB 970228
Reichart, Daniel E.
GRB 970228 is the first gamma-ray burst (GRB) for which prolonged postburst transient X-ray, optical, and infrared emission has been detected. Recent Hubble Space Telescope (HST) observations show that the transient consists of two components: a point source, which is known to be fading, and an extended source, which is possibly fading. I fit stan…
Electron Density Diagnostics for the Solar Upper Atmosphere from Spectra Obtained by SUMER/SOHO
Wilhelm, K.; Curdt, W.; Schühle, U. +3 more
We evaluate the electron density in various solar regions above the limb observed by the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) instrument on SOHO. We find in general good agreement among line ratios from Be-, B-, N-, and Mg-like ions, giving densities of order 108 cm-3.
The WC10 central stars CPD-56 deg8032 and He 2-113 - I. Distances and nebular parameters
Barlow, M. J.; De Marco, Orsola; Storey, P. J.
We present the results of an analysis of the WC10 central stars CPD-56 deg8032 and He 2-113 and of their surrounding planetary nebulae (PNe). UCL Echelle Spectrograph spectra with a resolving power of R=50 000, covering the wavelength range 3600-9500 A, were obtained for both objects. Expansion and radial velocities are derived from the nebular Ba…
Calibration of the Surface Brightness Fluctuation Method for use with the Hubble Space Telescope.
Lauer, Tod R.; Ajhar, Edward A.; Dressler, Alan +4 more
This paper presents the calibration of the surface brightness fluctuation (SBF) technique for use with the Wide Field and Planetary Camera-2 (WFPC-2) on the Hubble Space Telescope (HST). The calibration has a color term and zeropoint significantly different from the Kron-Cousins I-band SBF technique developed for ground-based observations. It is a…
Optical Spectroscopy of EZ Canis Majoris: Indication for Large-Scale Structures in a Wolf-Rayet Wind
St-Louis, Nicole; Morel, Thierry; Marchenko, Sergey V.
We have carried out optical spectroscopy of the Wolf-Rayet star EZ CMa during 20 consecutive nights in 1995 January in support of the IUE Mega-project. In parallel with this optical spectroscopy, we also monitored EZ CMa using narrowband photometry. The light curve was found to be remarkably stable when folded with the \Pscr=3.77 day period, and i…
A Massive Cluster of Galaxies at Z = 0.996
Dickinson, M.; Le Fèvre, O.; Crampton, David +1 more
We report the identification of a cluster of galaxies around the high-redshift radio galaxy 3CR 184 at z = 0.996. The identification is supported by an excess of galaxies observed in projection in I-band images (both in ground-based and Hubble Space Telescope [HST] data), a peak in the redshift distribution comprising 11 galaxies (out of 56 with m…
Hubble Space Telescope Imaging of the Globular Cluster System Around NGC 5846
Forbes, Duncan A.; Brodie, Jean P.; Huchra, John
Bimodal globular cluster metallicity distributions have now been seen in a handful of large ellipticals. Here we report the discovery of a bimodal distribution in the dominant group elliptical NGC 5846, using the Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2). The two peaks are located at V-I=0.96 and 1.17, which roughly corres…