Search Publications
The IUE Spectrum of the Planetary Nebula NGC 6905
Feibelman, Walter A.
We present results from new lUE high-dispersion and archival low-dispersion spectra of NGC 6905. Ultraviolet emission lines of O VIII and possibly O VII are detected for the first time in NGC 6905. High-excitation lines of C IV, C V, O VI, [Mg V], [Ne III], [Ne IV], [Ne V], [Ar IV], and [Ar V] are also observed. Electron densities and terminal win…
A first glimpse into ISM/ICM connections at z=0.2 with ISOCAM.
Altieri, B.; Aussel, H.; Elbaz, D. +10 more
Although it is well established that the cluster environment affects the gas content and massive star formation in galaxies, the mechanisms have not yet been unambiguously identified. In order to elucidate some of the processes responsible, an ISO Core Programme - DEEPXSRC - is dedicated to deep observations of medium redshift rich clusters of gal…
The variable Herbig AE star HR 5999. XII. Its circumstellar extinction law.
Perez, M. R.; The, P. S.; van den Ancker, M. E. +1 more
A study of the extinction law in the UV-visual-IR spectral regions has been made towards the variable Herbig Ae star HR 5999 at three brightness levels V=6.9mag, 7.2mag, and 7.3mag. For comparison we have made an equivalent study of its proper motion non-variable companion HR 6000, which is embedded in the same dark cloud. The extinction law towar…
Hubble Space Telescope Narrowband Imaging of the Planetary Nebula SMP 83/WS 35/N66
Vassiliadis, E.
LMC-SMP83 is a planetary nebula in the Large Magellanic Cloud whose central star is recently reported by Pena et al. to show decreases in temperature and luminosity of at least 50% over a time span of seven years. Serendipitously, this object is observed with the Planetary and Faint Object Cameras onboard the Hubble Space Telescope between 1991 Ju…
The Twin Astrographic Catalog (TAC) Version 1.0
Zacharias, N.; Wycoff, G. L.; Zacharias, M. I. +1 more
A first version of the Twin Astrographic Catalog (TAC) of positions for 705,679 stars within -18°≤δ≤90° has been produced. The sky coverage of the TAC is complete to over 90% in that area. The limiting magnitude is about B =12.0. Positions are based on 4912 plates taken with the U.S. Naval Observatory Twin Astrograph (blue, yellow lens) at epochs …
HD 159176: photospheric and wind-dominated light-curve analyses coupled to wind modelling
Pachoulakis, Ioannis
HD 159176 is a hot, massive, non-eclipsing binary with a small-amplitude ellipsoidal variability. The existing velocity solution determines the ratio of the stellar masses. In the present article these radial velocities, coupled with one optical and two UV light curves derived from IUE images in bandpasses devoid of stellar wind lines, are solved …
The Diverse Optical/Ultraviolet Spectra of the Globular Cluster X-ray Sources in NGC 7078 and NGC 6712
Anderson, Scott F.; Margon, Bruce; Downes, Ronald A.
Among the about one dozen luminous X-ray bursters in the cores of globular clusters, only three have optical/UV counterparts unambiguously identified. We have observed two of these counterparts spectroscopically with the low resolution optical and UV gratings of the Faint Object Spectrograph (FOS) aboard the Hubble Space Telescope (HST), yielding …
The ultraviolet absorption spectrum. of the z=2.72 QSO HS 1700+6416 II. Sulfur and neon in heavy-element absorbing systems.
Reimers, D.; Wamsteker, W.; Koehler, S.
We present ultraviolet spectra of the bright high-redshift QSO HS 1700+6416 obtained with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope. These observations cover the wavelength range 1160-1680A at a resolution R=~2000 with a maximum signal-to-noise per pixel of 8 in the raw data and 15 in smoothed data. The pre…
Spatial evolution of the magnetic field spectral exponent in the solar wind: Helios and Ulysses comparison
Tu, C. -Y.; Marsch, E.
The spatial evolution of the spectral exponent of magnetic field fluctuations in the solar wind is investigated by a comparison of spectra and length functions obtained from Helios for in-ecliptic and from Ulysses for high-latitude observations. A similar radial evolution trend is found in both data sets for the Bz component of the magn…
Spectroscopic binary orbits from ultraviolet radial velocities. Paper 20: HD 149404
Stickland, D. J.; Koch, R. H.