Search Publications
The effective temperatures of O-type stars from UV spectroscopy
Bianchi, Luciana; Garcia, Miriam
We present an analysis of high resolution spectra in the far-UV - UV range (∼905-2000 Å) with non-LTE, spherical, hydrodynamical, line-blanketed models, of three O-type Galactic stars, and derive their photospheric and wind parameters. These data extend previously analyzed samples and fill a gap in spectral type coverage. The combined sample confi…
A statistical study of C IV regions in 20 Oe-stars
Popović, L. Č.; Antoniou, A.; Stathopoulos, D. +3 more
In this paper, using the Gauss-Rotation model (GR model), we analyse the UV C IV resonance lines in the spectra of 20 Oe-stars of different spectral subtypes, in order to detect the structure of C IV region. We study the presence and behavior of absorption clouds and analyse their characteristics. From this analysis we can calculate the values of …
The metallicity of β Cephei stars on the basis of the satellite ultraviolet spectra
Niemczura, E.; Cugier, H.; Daszyńska, J.
We derive the mean stellar parameters like angular diameter, effective temperature, and metallicity from ultraviolet spectra for all β Cephei stars observed during the IUE satellite mission, including those belonging to the three open clusters. For this purpose we fit the theoretical flux distributions of Kurucz's models to observed low-resolution…
Ultraviolet light curves of eclipsing binary stars. I. The catalogue of IUE data
Połubek, Grzegorz
The catalogue contains eclipsing and ellipsoidal variable stars observed by International Ultraviolet Explorer satellite (IUE). As examples we discuss IUE data for Algol (β Persei) and MR Cygni.
The mean stellar parameters from IUE and hipparcos data
Niemczura, E.; Cugier, H.; Daszyńska, J.
Far-Ultraviolet light curves of the δ Scuti variable: β Cassiopeiae
Cugier, H.; Daszyńska, J.
Multiwavelength properties of blazars
Urry, C. Megan
The multiwavelength spectra of blazars appear to be dominated by nonthermal emission from a relativistic jet oriented close to the line of sight. The recent detection of many blazars at gamma-ray energies strongly supports this scenario. High quality multiwavelength monitoring data for the brightest one or two blazars suggest the optical through X…
AGN watch continuum monitoring of radio-quiet and radio-loud AGN
O'Brien, Paul T.; Leighly, Karen M.
The International AGN Watch has monitored a number of radio-quiet and radio-loud Active Galactic Nuclei - the most luminous objects in the universe. We present a review of the main observational results from the continuum monitoring campaigns, concentrating on those which aim to quantify the simultaneous ultraviolet to X-ray variability characteri…
Rapid continuum variability in NGC 4151
Crenshaw, D. M.; Malkan, M.; Warwick, R. +4 more
Intensive monitoring of NGC 4151 showed strong, correlated variability at X-ray, ultraviolet, and optical wavelengths. The strongest variations were seen in ~1.5 keV X-rays, with weaker variations at ~100 keV and no significant variability in the 0.1-1 keV bands. In the ultraviolet/optical regime, the fractional variability amplitude decreased fro…
On an improved geostationary catalog
Sochilina, A. S.; Kiladze, R. I.; Grigoriev, K. V. +1 more
In the previous geostationary catalog 1994 a possibility to calculate the evolution of orbital data with the aid of the initial improved orbits for a long-term interval was shown. This catalog was used for the identification of 12 000 photographic observations and for the ephemeris prediction. The new catalog of improved orbits is based on a more …