Search Publications
The spectrum of HD46223
Zagury, Frédéric
The spectrum of HD46223 was established from the optical to the far UV and normalized by the spectrum of a non-reddened star of same spectral type. The resulting spectrum is separated into two components. One is the direct starlight. The second is an additional component of light scattered at small angles. In the optical the spectrum is dominated …
Scattered starlight contamination in the spectrum of reddened stars
Zagury, Frédéric
The comparison, undertaken in preceding papers, of the UV observations of nebulae and of reddened stars reveals contradictory aspects of interstellar extinction. The aim of this paper is to understand the implications hidden behind the apparent contradictions. The questions treated will be: how can small grains with an isotropic phase function mak…
Rapid photometry of supernova 1987A: a 2.14 ms pulsar?
Kristian, Jerome A.; Danks, Anthony C.; Kunkel, William E. +9 more
We have monitored Supernova 1987A in optical/near-infrared bands using various high-speed photometers from a few weeks following its birth until early 1996 in order to search for a pulsar remnant. While we have found no clear evidence of any pulsar of constant intensity and stable timing, we have found emission with a complex period modulation nea…
The UV spectrum of nebulae
Zagury, Frédéric
This paper presents an analysis of the UV spectrum of some nebulae with clearly identified illuminating stars, all observed by the IUE satellite. The data show remarkable properties of the UV spectrum of the nebulae. Each spectrum is the product of the star spectrum and a linear function of 1/ λ. There is no peculiar behaviour in the spectrums at …
Interpretation of the UV spectrum of some stars with little reddening
Zagury, Frédéric
The UV spectrum of a few reddened stars will be decomposed into two terms. One is the direct starlight, F ★,λ0 e-τ λ, which is the product of the flux of the star corrected for interstellar extinction, F★, λ0, and of the extinction e - τλ. The second is starlig…
A survey of unresolved objects in the Hubble Deep Field South
Elson, Rebecca A. W.; Tanvir, Nial R.; Johnson, Rachel A. +1 more
We present a survey of unresolved objects in the Hubble Deep Field South. We find 39 such objects with V606>27.3. Of these, 29 are candidate main-sequence stars. Their number counts are consistent with no extended stellar halo around the Galaxy, in agreement with analyses of the Hubble Deep Field North. We identify 6 objects which ha…
Stellar radii of M giants
Schild, H.; Dumm, T.
We determine the stellar radii of the M giant stars in the Hipparcos catalogue3 that have a parallax measured to better than 20% accuracy. This is done with the help of a relation between a visual surface brightness parameter and the Cousins ( V - I) colour index, which we calibrate with M giants with published angular diameters. The ra…
The Coma Berenices star cluster and its moving group
Soubiran, C.; Odenkirchen, M.; Colin, J.
We report on the analysis of astrometric and photometric data from Hipparcos, Tycho and the ACT catalogue in a 1200 sq. degree field around the nearby open star cluster in Coma Berenices and infer the characteristic features of this cluster. From a sample of 51 kinematic members we derive the cluster's distance, size and spatial structure as well …
Detection of the lensing galaxy for the double QSO HE 1104-1805
Surdej, J.; Grundahl, F.; Hjorth, J. +5 more
High angular resolution ground-based direct imaging ( V, R, Ic) of the double QSO HE 1104-1805 has been obtained with the NOT and NTT telescopes. Analysis of these data led to the first detection of the lensing galaxy. Direct imaging of HE 1104-1805 has subsequently been carried out with the Planetary Camera (WFPC2) through the F555W (n…
Hipparcos data for two open clusters containing cepheids
Lindegren, L.; Lyngå, G.
Using proper motion data from the Hipparcos satellite it is shown that the cepheids S Nor and U Sgr are members of the open clusters NGC 6087 and M 25, respectively. The precision of the Hipparcos data is needed to conclusively carry out a membership test. Parallax data, also obtained from Hipparcos, do not contradict the proper motion results.