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Optical positions of compact extragalactic radio sources with respect to the HIPPARCOS Catalogue
Costa, E.; Loyola, P.
Optical positions relative to the Hipparcos Catalogue, and therefore within the International Celestial Reference System (ICRS), have been obtained for the optical counterparts of 25 compact extragalactic radio sources (CERS) south of delta ~ +10degr . Most of these sources are being monitored as Benchmark objects for the establishment of a unifie…
Crowded-field photometry from HST-imaging
Thomsen, B.; Sodemann, M.
We present a thorough investigation of stellar photometry based on HST imaging of crowded fields at 85arcsec and 10arcsec from the centre of the high-surface brightness elliptical galaxy M 32. The Principal Investigators of the present archive data have elsewhere presented an impressive colour-magnitude diagram of the field at 85arcsec . Based on …
Reduction of the Astrographic Catalogue, zone of S. Fernando
Vieira, K.; Abad, C.; Zambrano, A.
The San Fernando Zone of the Astrographic Catalogue is reduced to the HIPPARCOS system in order to test a reduction model previously presented by Abad (1993). A new method for the determination of field distortion and magnitude or color dependent systematic errors on photographic plates is discussed.
Mesures d'etoiles doubles effectuees a la lunette de 50 CM de l'Observatoire de Nice (2({) e. Measures of visual double stars made with the 50 CM refractor at the Nice Observatory (2^{nd
Thorel, J. -C.
66 measures of 38 visual double stars made at the Observatoire de la Cote d'Azur, at Nice, in september et december 1997, with the 50 cm equatorial refractor equipped with filar micrometer and electronic recording device. Observation programmes of stars suspected double and new binaries discovered by Hipparcos, and measures of double stars which h…
Stellar uvbybeta photometry in three EUV shadow directions
Knude, J.
We present the uvbybeta data used to locate the dust and derive distances for nearby diffuse interstellar clouds in the EUV shadows lb27-31, lb165-32 and lb329+46 discovered by the Extreme Ultraviolet Explorer. The photometrically derived parallaxes of our program stars are compared to the parallaxes listed in the Hipparcos Catalog. Within the pho…
The solar disk spectrum between 660 and 1175 Anstroms (first order) obtained by SUMER on SOHO
Wilhelm, K.; Curdt, W.; Lemaire, P. +3 more
SUMER -- Solar Ultraviolet Measurements of Emitted Radiation -- onboard of SOHO -- Solar and Heliospheric Observatory -- obtained its first spectrum on January 25, 1996 near the north polar limb. The range from 660 Angstroms to 1175 Angstroms which has never before been observed with such a good spectral resolution contains a wealth of spectroscop…
An adaptive grid code for high resolution 1-D hydrodynamics of the solar and stellar transition region and corona
Peres, G.; Reale, F.; Betta, R. +1 more
We present a new version of the Palermo-Harvard hydrodynamic model of plasma confined in coronal loops, based on a regridding algorithm which ensures limited variations of thermodynamical variables across grid points. The code provides an accurate description of the dynamics of the chromosphere-corona transition region, in spite of the very steep …
Radial velocities and iron abundances of field RR Lyraes. I.
Barnes, T. G.; Fernley, J.
We present systemic velocities and iron abundances for 56 RR Lyraes, the majority of which have been observed by the HIPPARCOS satellite. Comparison between our systemic velocities and previous values identifies several binary candidates only one of which, TU UMa, was previously suspected of being a binary. However, spectra of the unusual RR Lyrae…
Mesures de vitesses radiales. VIII. Accompagnement AU sol du programme d'observation du satellite HIPPARCOS
Duflot, M.; Burnage, R.; Genty, V. +2 more
We publish 1879 radial velocities of stars distributed in 105 fields of 4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbach et al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90} using the Fehrenbach objective prism method. Table 1 only available in electronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5…
Analyzing X-ray variability by linear state space models
Timmer, J.; Konig, M.
In recent years, autoregressive models have had a profound impact on the description of astronomical time series as the observation of a stochastic process. These methods have advantages compared with common Fourier techniques concerning their inherent stationarity and physical background. However, if autoregressive models are used, it has to be t…