Search Publications
Radial-velocity curves for the classical Cepheids T Vul, TT Aql and Y Oph.
Evans, N. R.; Lyons, R.
Radial-velocity curves for three classical Cepheids, T Vul, Y Oph, and TT Aql, have been obtained. Mean values of the systemic velocity of Y Oph are in marginally better agreement with a constant value than with the orbit suggested by Abt and Levy. IUE spectra show no sign of a main-sequence companion B8 or earlier.
The narrow line active galaxies NGC 3081 and NGC 4507 : from the infrared to the UV.
Durret, F.; Bergeron, J.
The authors present optical data on NGC 3081 and NGC 4507, acquired as part of a long slit spectroscopic search for extended ionized line emission around active galactic nuclei. For both AGNs an extended ionized region surrounding the nucleus was detected together with ionized gas in the ring of NGC 3081 and in the spiral arms of NGC 4507. The aut…
Studies of the Chamaeleon star-forming region. II. The pre-main-sequence stars HD 97048 and HD 97300.
The, P. S.; Wesselius, P. R.; Tjin-A-Djie, H. R. E. +1 more
Photometric observations in the visual, near infrared, and far infrared (IRAS), and UV(IUE) and IDS spectra are presented of the pre-main-sequence stars HD 97048 and HD 97300. The spectral energy distribution between 0.1 and 100 µm is obtained, and corrected for foreground and circumstellar extinction. Distances are derived and the infrared …
The optical and X-ray decline of V 0332+53 (X 0331+53, BQ Cam).
van der Klis, M.; Charles, P. A.; Corbet, R. H. D.
The authors present optical spectra of the X-ray transient V 0332+53 (BQ Cam). The equivalent width of the Hα emission line in the spectrum has declined by a factor ≡2 compared with previous observations. This is interpreted as showing that V 0332+53 is surrounded by an evolving circumstellar envelope. EXOSAT observations failed to detect X-ray em…
X-Ray Spectral Observations of the Crab-like Supernova Remnants G21.5-0.9 and 3C 58
Becker, R. H.; Smith, A.; Davelaar, J.
Broad-band (2 - 10 keV) spectral data of the Crab-like supernova remnants 3C 58 and G21.5-0.9 have been obtained from the medium-energy instrument on EXOSAT. Both objects show a simple power-law spectrum with a spectral index of 0.72±0.12 for G21.5-0.9 and 1.30±0.26 for 3C 58. VLA 21 cm absorption measurements for G21.5-0.9 indicate a distance of …
High-Dispersion Observations of Alpha Bootis (K1 III) with the International Ultraviolet Explorer
Jordan, C.; Linsky, J. L.; Brown, A. +2 more
The authors have obtained very deeply exposed IUE echelle spectrograms of the bright, early-K giant Arcturus. They did not detect significant flux in the most prominent high-excitation species of a solar-like transition zone, C IV λ1548.2. The presence of a weak feature of Si III] λ1892.0, and possibly also Si IV λ1393.8, indicates the existence o…
On the Ultraviolet Spectra of Type I Supernovae
Branch, D.; Venkatakrishna, K. L.
A synthetic-spectrum technique, applied previously to the interpretation of the optical spectra of Type I supernovae, has been extended to the maximum-light near-ultraviolet spectrum. Spectral features in the interval 2750-3450 A are suggested to be complex blends of overlapping P Cygni profiles produced by numerous Fe II and Co II lines. This int…
A multi-wavelength study of the long-period AM HER system E2003+225 -I. The soft X-ray light curve and overall energy spectrum.
Mukai, K.; Maraschi, L.; Chiappetti, L. +10 more
X-ray, UV and optical data are presented of the longest period AM Her object, E2003+225, from October 12, 1983, together with a new linear polarization ephemeris. The optical and X-ray data were obtained simultaneously and the UV observations were carried out on the same day. A 6-hr observation with the Exosat 500 line/mm objective grating restric…
Variability of the BL Lacertae Objects PKS 2155-304 and OJ 287 in the Far-Ultraviolet
Maraschi, L.; Tanzi, E. G.; Tagliaferri, G. +1 more
All the ultraviolet spectra of the two bright BL Lacertae objects PKS 2155 - 304 and OJ 287 taken with the International Ultraviolet Explorer in the period 1978-1984 are examined. For each spectrum the best-fitting power law is determined and a correlation between spectral slope and intensity is searched for. The correlation, if present, is weak. …
IUE Observations of Interstellar Hydrogen and Deuterium toward Alpha Centauri B
Moos, H. W.; Murthy, J.; Linsky, J. L. +3 more
A high dispersion profile is presented of the Lyman-alpha emission toward Alpha Cen B as recorded in two images taken with the IUE spacecraft. The spectra were examined with a three-parameter Gaussian or five-parameter solar-type profile to derive the intrinsic background stellar emission. Voight absorption profiles were calculated for the interve…