Search Publications
Titan's rotation. A 3-dimensional theory
Vienne, A.; Noyelles, B.; Lemaître, A.
Aims:We study the forced rotation of Titan seen as a rigid body at the equilibrium Cassini state, involving the spin-orbit synchronization.
Methods: We used both the analytical and the numerical ways. We analytically determined the equilibrium positions and the frequencies of the 3 free librations around it, while a numerical integration assoc…
Abundances in planetary nebulae: NGC 6826
Pottasch, S. R.; Surendiranath, R.
Aims: We determine the chemical abundances and other parameters of the nebula NGC 6826 and its central star.
Methods: We present new ISO spectra and combine them with archival IUE and optical spectra from the literature to get a complete, extinction-corrected, spectrum. The chemical composition of the nebula is then calculated in two ways, fir…
A twelve-image gravitational lens system in the z ≃ 0.84 cluster Cl J0152.7-1357
Demarco, R.; Lidman, C.; Grillo, C. +6 more
Context: Gravitational lens modeling is presented for the first discovered example of a three-component source for which each component is quadruply imaged. The lens is a massive galaxy member of the cluster Cl J0152.7-1357 at z ≃ 0.84.
Aims: Taking advantage of this exceptional configuration and of the excellent angular resolution of the HST …
The redshifted network contrast of transition region emission
Dwivedi, B. N.; Marsch, E.; Curdt, W. +1 more
Aims: We study the VUV emission of the quiet Sun and the net redshift of transition region lines in the SUMER spectral range. We aim at establishing a link with atmospheric processes and interpreting the observed downflow as the most evident part of the prevailing global coronal mass transport.
Methods: We rank and arrange all pixels of a mono…
The most rapidly rotating He-strong emission line star: HR 7355
Baade, D.; Rivinius, T.; Townsend, R. H. D. +1 more
Aims: We searched for massive stars with Balmer emission consistent with magnetically confined circumstellar material.
Methods: Archival spectroscopic and photometric data were investigated.
Results:
Time dependent model of the interplanetary Lyman α glow: applications to the SWAN data
Izmodenov, V.; Quémerais, E.; Koutroumpa, D. +1 more
Aims: Previous results of the study of interplanetary Lyman α background data obtained by the SWAN-SOHO between 1996 and 2005 clearly show that the solar cycle variations of the solar parameters deeply affect the interplanetary background emission. In this work, we compare these observational results with a time-dependent modeling of the interplan…
Heavy absorption and soft X-ray emission lines in the XMM-Newton spectrum of the type 2 radio-loud quasar 3C 234
Fiore, F.; Bianchi, S.; Guainazzi, M. +4 more
Aims:We report results on a 40 ks XMM-Newton observation of the type 2 quasar 3C 234. Optical spectropolarimetric data have demonstrated the presence of a hidden broad-line region in this powerful (MV ≤ -24.2 after reddening and starlight correction) narrow-line FRII radio galaxy. Our analysis is aimed at investigating the X-ray spectra…
A solar burst with a spectral component observed only above 100 GHz during an M class flare
Mandrini, C. H.; Giménez de Castro, C. G.; Cristiani, G. +4 more
Context: Since the installation of submillimeter solar radio telescopes, a new spectral burst component was discovered at frequencies above 100 GHz, creating the THz burst category. In all the reported cases, the events were X-class flares and the THz component was increasing.
Aims: We report for the first time an M class flare that shows a di…
Follow-up observations of binary ultra-cool dwarfs
Martín, E. L.; Huélamo, N.; Bouy, H. +12 more
Context: Astrometric observations of resolved binaries provide estimates of orbital periods and will eventually lead to measurement of dynamical masses. Only a few very low mass star and brown dwarf masses have been measured to date, and the mass-luminosity relation still needs to be calibrated.
Aims: We have monitored 14 very low mass multipl…
Discovery of ultra-compact nuclear rings in three spiral galaxies
Knapen, J. H.; Comerón, S.; Beckman, J. E. +1 more
Ring-shaped morphologies of nuclear star-forming regions within the central 40{-}200 pc of disk galaxies have been barely resolved so far in three composite Sy 2 nuclei, the Sy 2 Circinus galaxy and in three non-AGN galaxies. Such morphologies resemble those of the standard 1 kpc-size nuclear rings that lie in the inner Lindblad resonance regions …