Showing papers in "Monthly Notices of the Royal Astronomical Society in 1983"
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TL;DR: In this paper, the radial velocity curves, in spite of their small amplitudes, are weil defined and do not show any peculiarities, and the accuracy of observations seems to be sufficient for determining both the moments of particular phases and the amplitudes.
Abstract: The radial velocity curves, in spite of their small amplitudes, are weil defined and do not show any peculiarities. The accuracy of observations seems to be sufficient for determining both the moments of particular phases and the amplitudes (about 3 km/s for v Cen and 6 km/s for (3 Cen). Points denote velocities actually observed, the broken line is a sinusoid fitted by eye to the observations. Both objects are bright, so the exposure times were typically 2-3 min.
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TL;DR: In this paper, the authors discute des contraintes generales sur la variabilite impliquant l'efficacite de la conversion masse au repos-energie, the geometrie et les effets des paires.
Abstract: Les spectres des sources compactes qui rayonnent au-dessus de 511 keV peuvent etre modifies par les paires electron-positron crees par les collisions photon-photon. L'opacite Thomson due aux paires peut facilement depasser l'unite dans des sources comme les noyaux galactiques actifs. La coupure spectrale aux hautes energies est inversement reliee a la luminosite de la source. On discute des contraintes generales sur la variabilite impliquant l'efficacite de la conversion masse au repos-energie, la geometrie et les effets des paires. Les corrections relativistes peuvent etre grandes, meme dans une source isotrope
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TL;DR: In this article, a serie de plus de 30 simulations of collision and fusion of paires de galaxies disque-halo semblables is presented, and the authors analyse de facon detaillee certains aspects des processus d'interaction comme la formation de ponts et de queues and the perte et transfert de la masse, de lenergie and du moment angulaire a l'interieur de la paire.
Abstract: On a effectue une serie de plus de 30 simulations de la collision et du fusionnement de paires de galaxies disque-halo semblables. On analyse de facon detaillee certains aspects des processus d'interaction comme la formation de ponts et de queues et la perte et transfert de la masse, de l'energie et du moment angulaire a l'interieur de la paire. On analyse aussi la forme et la structure des vitesses des restes du fusionnement et leur variation avec les conditions initiales
TL;DR: In this paper, the authors give simple but accurate numerical fits to various two-body rates in relativistic thermal plasmas, in the temperature range kTe ~ 50 keV −1MeV.
Abstract: We give simple but accurate numerical fits to various two-body rates in relativistic thermal plasmas, in the temperature range kTe ~ 50 keV–1MeV. The processes we discuss are bremsstrahlung, Coulomb heating and electron-positron pair production and annihilation. In particular we present a fit to the thermal electronelectron bremsstrahlung spectrum which is accurate to better than 5 per cent. We also include the results of some other workers, for completeness. Our results are suitable for semi-analytic or computer modelling of hot plasmas.
TL;DR: Etude numerique de rencontres gravitationnelles de paires de binaires dures ayant des energies inegales mais des masses egales as mentioned in this paper.
Abstract: Etude numerique de rencontres gravitationnelles de paires de binaires dures ayant des energies inegales mais des masses egales
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TL;DR: In this article, the authors show that large density fluctuations of mass-scale 0.1 solar mass arise in any collapsing cloud with metallicity not greater than 0.001 of the solar value.
Abstract: Primordial clouds are likely to be remarkably uniform over stellar mass-scales in the absence of a pre-existing generation of stars. Thermal instability is found to occur during the collapse of a primordial cloud when the H2 abundance is rising and the H2 optical depth is of order unity. The e-folding rate for fluctuation growth exceeds the free-fall collapse rate by an order of magnitude. Large density fluctuations of mass-scale 0.1 solar mass arise in any collapsing cloud with metallicity not greater than 0.001 of the solar value. Gravitational instability ensures that many of the clumps coagulate to form protostars of masses extending up to the initial Jeans mass when the fluctuations develop, namely 100 solar masses. The primordial IMF should therefore have spanned the mass range from 0.1 to 100 solar masses, but may have been dominated by the more massive stars.
TL;DR: In this article, a mesure les deplacements vers le rouge for un nouvel echantillon de 320 galaxies, complet a J≃17, was presented.
Abstract: On a mesure les deplacements vers le rouge pour un nouvel echantillon de 320 galaxies, complet a J≃17. On a evalue la fonction de correlation a 2 points en utilisant les informations relatives aux positions et aux deplacements vers le rouge. On en deduit la valeur quadratique moyenne des vitesses particulieres relatives pour des paires de galaxies dont les separations projetees sont dans le domaine 0≤σ≤4 h −1 Mpc. On trouve des differences de vitesses sur la ligne de visee 1/2 =250±50 kms −1 independantes des separations projetees. On a evalue l'amplitude de la fonction de correlation a 3 points