9310083 Matzner A study will be performed of relativistic systems, especially as applied to the interaction of black holes, cosmology and the formation of the elements in cosmology, and to tests of General Relativity in near Earth experiments. The black hole and cosmological studies will be primarily numerical. In order to predict the expected gravitational wave signals in the LIGO detector, the orbital dynamics and merger of astrophysical black holes will be numerically simulated. A number of techniques, including adaptive multigrid finite differencing will be employed (Adaptive multigrid permits arbitrarily fine resolution at important points in the simulation). Obtaining useful signal predictions from black hole evolution requires extremely high accuracy in the numerical development. The codes will be implemented on massively parallel computers (such as the Thinking Machine CM 5) which have the memory and the computing power to handle these large scale simulations. The end product will be a catalog of wave forms, relevant to producing appropriate detection algorithms for LIGO. This waveform catalog in particular will allow extraction of binary orbital information as well as of the black hole characteristics before and after merger of the two holes. Cosmological studies will concentrate on the formation of elements in the early universe, particularly in maintaining and upgrading existing computer codes at Texas. Areas to be emphasized will be newly measured nuclear reaction rates, the extension of nuclear reaction chains to include heavier elements, the refinement of numerical techniques in these codes, and the porti ng of the nucleosynthesis codes to large parallel machines. Other aspects of cosmology to be studied include the formation of structure in the early universe and the implementation of computer codes accurately describing it; and the statistics of gravitational lensing, (multiple images of distant QSOs caused by an intervening cluster of galaxies), and models of gravitational lenses. ***
