Search Publications
Stellar luminosity functions of rich star clusters in the Large Magellanic Cloud
Santiago, B.; Gilmore, G. F.; Beaulieu, S. +1 more
We show the results of deep V and I HST photometry of 6 rich star clusters in the Large Magellanic Cloud with different ages and metallicities. The number of stars with measured magnitudes in each cluster varies from about 3000 to 10 000 stars. We build stellar density and surface brightness profiles for the clusters and extract half-light radii a…
An analysis of HST UV spectra of Cyg OB2 stars
Kudritzki, R. P.; Herrero, A.; Puls, J. +2 more
As a first step of a vigorous program to investigate the Wind Momentum - Luminosity Relationship (WLR) of Galactic O-stars by analyzing stars belonging to the same cluster we present UV HST observations of six supergiants and one giant in the
Multi-wavelength bispectrum speckle interferometry of R Leo and comparison with Mira star models
Weigelt, G.; Hofmann, K. -H.; Balega, Y. +1 more
We present diffraction-limited (30 mas resolution) bispectrum speckle interferometry of the Mira star R Leo with the 6 m SAO telescope. The speckle interferograms were recorded through narrow-band interference filters with centre wavelength/bandwidth of 673 nm/8 nm (strong TiO absorption band), 656 nm/10 nm, 699 nm/6 nm and 781 nm/14 nm (moderate …
Dynamical variations of the differential rotation in the solar convection zone
Covas, E.; Moss, D.; Tavakol, R.
Recent analyses of helioseismological observations seem to suggest the presence of two new phenomena connected with the dynamics of the solar convective zone. Firstly, there are present torsional oscillations with periods of about 11 years, which penetrate significantly into the solar convection zone and secondly, oscillatory regimes exist near th…
ISO/SWS observations of SN 1987A. II. A refined upper limit on the mass of 44Ti in the ejecta of SN 1987A
Sollerman, J.; Lundqvist, P.; Fransson, C. +1 more
ISO/SWS observations of SN 1987A on day 3425 show no emission in [Fe I] 24.05 mum and [Fe II] 25.99 mum down to the limits ~ 0.39 Jy and ~ 0.64 Jy, respectively. Assuming a homogeneous distribution of 44Ti inside 2000 km s-1 and negligible dust cooling, we have made time dependent theoretical models to estimate an upper limit…
Comets in full sky Lalpha maps of the SWAN instrument. I. Survey from 1996 to 1998
Schmidt, W.; Bertaux, J. -L.; Lallement, R. +5 more
The SWAN instrument onboard the SOHO spacecraft is a Lyman alpha scanning photometer cabable of mapping the whole sky with 1degr resolution. Since January 1996 the instrument has produced on average three full sky maps a week with the principal scientific objective of observing the distribution of heliospheric neutral hydrogen. In addition, these …
HST study of the LMC compact star-forming region N83B
Schaerer, D.; Heydari-Malayeri, M.; Charmandaris, V. +3 more
High resolution imaging with the Hubble Space Telescope has uncovered the thus far hidden stellar content and the nebular features of the high excitation compact H ii region N83B in the Large Magellanic Cloud (LMC). We discover that the H ii region is powered by the most recent massive starburst in the OB association LH 5 and the burst has created…
Inhomogeneous metal enrichment at z ~ 1.9: The Lyman limit systems in the spectrum of the HDF-S quasar
D'Odorico, V.; Petitjean, P.
We present a detailed analysis of three metal absorption systems observed in the spectrum of the HDF-South quasar J2233-606 (z_em=2.238), taking advantage of new VLT-UVES high resolution data (R=45 000, S/N=40-60, lambda lambda 3050-10 000 Å). Three main components, spanning about 300 km s-1, can be distinguished in the Lyman limit syst…
21-cm H I emission from the Damped Lyman-alpha absorber SBS 1543+593
Jenkins, E. B.; Brinks, E.; Bowen, D. V. +2 more
We detect 21-cm emission from the Low Surface Brightness (LSB) galaxy SBS 1543+593, which gives rise to a Damped-Lyalpha (DLyalpha ) absorption line in the spectrum of the background QSO HS 1543+5921 (ze = 0.807). We obtain an accurate measure of the velocity of the H I gas in the LSB galaxy, v = 2868 km s-1, and derive a mas…
HST observations of the LMC compact \ion{H}{ II} region N 11A
Schaerer, D.; Heydari-Malayeri, M.; Charmandaris, V. +3 more
We present a study of the LMC compact H ii region N 11A using Hubble Space Telescope imaging observations which resolve N 11A and reveal its unknown nebular and stellar features. The presence of a sharp ionization front extending over more than 4'' (1 pc) and fine structure filaments as well as larger loops indicate an environment typical of massi…