Numerical study of evolution of proto-galaxies and proto-clusters for observational cosmology in the next generation.

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The prinicpal goal of the present project is to develop a cosmological hydrodynamic code which is indispensible in quantitatively examining the evolution of proto-galaxies and proto-clusters, and to construct a theoretical model which can approach the above problem in a analytical and complementary manner. To be more specific, the results of our research are summarized as follows :(1) We have written up a cosmological code which is based on the smoothed particle hydrodynamic method and can properly take into account the gas-radiative processes.(2) We have derived analytical expressions for formation and destruction rates of gravitationally bound objects. Combining with the nonlinear spherical model, we computed the thermal bremsstrahlung spectrum emitted from individual proto-clusters of galaxies, and then made theoretical predictions of the cosmic X-ray background flux and spectrum due to the clusters of galaxies.(3) While the recent discovery of the Cepheid variables in the Virgo clu … More ster galaxies puts additional support for the Hubble constant H_0 - 80km/sec/Mpc, a relatively lower value H_0 - 50km/sec/Mpc is suggested by other distance indicators. In order to explore an idea that locally determined H_0 is significantly different from its global average, we considered a model of a locally open universe embedded in the spatially flat universe. We found analytic expressions for the lower limit on the global Hubble constant, and the upper limit on the age of the universe with a given value for the Hubble constant in the local universe.We calculated the gravitational wave form from a rotationally collapsing supernova core. Comparing the results for various angular momentum distributions, we found that LIGO can detect such a signal provided that a rotating supernova occurs in our galaxy. On the other hand, we have developed a new general relativistic hydrodynamics code in which spherical symmetry is assumed and fully implicit scheme is adopted. We think this code is useful to study the delayd mechanism. Less