N. Sugiyama

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Cosmic microwave background (CMB) anisotropies and density uctuations are calculated for at cold dark matter (CDM) models with a wide range of parameters , i.e., 0 ; h and B for both standard recombination and various epochs of reionization. Tables of the power spectrum of CMB anisotropies in the form of C ` 's as a function ofàre presented. Although the(More)
We use cosmological simulations to study the origin of primordial star-forming clouds in a ΛCDM universe, by following the formation of dark matter halos and the cooling of gas within them. To model the physics of chemically pristine gas, we employ a non-equilibrium treatment of the chemistry of 9 + 2 , H −) and include cooling by molecular hydrogen. By(More)
We classify the future of the universe for general cosmological models including matter and dark energy. If the equation of state of dark energy is less then −1, the age of the universe becomes finite. We compute the rest of the age of the universe for such universe models. The behaviour of the future growth of matter density perturbation is also studied.(More)
The late-time entropy production by the massive particle decay induces the various cosmological effects in the early epoch and modify the standard scenario. We investigate the thermalization process of the neutrinos after the entropy production by solving the Boltzmann equations numerically. We find that if the large entropy are produced at t ∼ 1 sec, the(More)
The origin of the substantial magnetic fields that are found in galaxies and on even larger scales, such as in clusters of galaxies, is yet unclear. If the second-order couplings between photons and electrons are considered, then cosmological density fluctuations, which explain the large-scale structure of the universe, can also produce magnetic fields on(More)
We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At Ω 0 ∼ 0.3 – 0.4, the COBE normalized open model appears to be consistent with most observations. Subject headings: cosmic microwave background —(More)