Problems in Gravitation (Physics)

9310083 Matzner 将进行相对论系统的研究，特别是应用于黑洞相互作用、宇宙学和宇宙学中元素的形成，以及近地实验中广义相对论的测试。 黑洞和宇宙学研究将主要是数值研究。 为了预测LIGO探测器中预期的引力波信号，将对天体物理黑洞的轨道动力学和合并进行数值模拟。 将采用多种技术，包括自适应多重网格有限差分（自适应多重网格允许在模拟中的重要点上实现任意精细的分辨率）。 从黑洞演化中获得有用的信号预测需要极高的数值开发精度。 这些代码将在大规模并行计算机（例如 Thinking Machine CM 5）上实现，这些计算机具有处理这些大规模模拟的内存和计算能力。 最终产品将是一个波形目录，与为 LIGO 生成适当的检测算法相关。 该波形目录特别允许提取双轨信息以及两个黑洞合并之前和之后的黑洞特征。 宇宙学研究将集中于早期宇宙中元素的形成，特别是维护和升级德克萨斯州现有的计算机代码。 需要强调的领域将是新测量的核反应速率、核反应链的扩展以包括较重的元素、这些代码中数值技术的改进以及将核合成代码移植到大型并行机器。 宇宙学的其他方面需要研究，包括早期宇宙结构的形成以及准确描述它的计算机代码的实现；以及引力透镜的统计数据（由星系团引起的遥远 QSO 的多个图像）以及引力透镜模型。 ***

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. ***