The LIGO-VIRGO Scientific Collaboration recently reported the first two direct detections of gravitational wave (GW) signals and demonstrated that these events (GW150914 and GW151226) were produced by the inspiral and coalescence of binary black holes. This breakthrough marks the beginning of the era of GW astronomy. The planned research bridges the fields of general relativity and astrophysics, by studying the generation of gravitational waves, relativistic hydrodynamics, and relativistic magnetohydrodynamics. A common thread uniting the different theoretical topics is the crucial role of gravitation, especially relativistic gravitation. This award provides major funding for research in general relativity at UIUC and a significant component of the total support in theoretical astrophysics to that institution. An appreciable portion of the funding is devoted to the education, training and support of undergraduate, graduate, and postdoctoral students. These students collaborate with the PI on the majority of research topics funded by the project. The grant supports the activities of the PI's Research Experiences for Undergraduates (REU) team at UIUC in computational astrophysics and general relativity theory. The training that each of the PI's undergraduate, graduate, and postdoctoral students receives in large-scale computations and scientific visualization, as well as in several different areas of theoretical physics and astrophysics, prepares them to pursue professional careers in a broad range of scientific and technical fields. The computer algorithms and numerical codes that are developed are useful to other groups working in computational physics and astrophysics. Through the research and outreach activities of the PI and his group, the grant helps promote the use of computers and visualization tools at all levels of education, as well as the public awareness of some the latest and most exciting developments in gravitation physics and astrophysics.
Compact objects provide the principal forum of the studies, and the dynamics of matter in a strong gravitational field is a major theme. Some of the topics for investigation include the inspiral and coalescence of compact binaries (binary black holes, binary neutron stars and binary black hole--neutron stars), the generation of gravitational waves from binaries and other promising astrophysical sources and the accompanying electromagnetic signals, gravitational collapse, the stability of rotating, relativistic stars and the evolution and final fate of unstable stars, gamma-ray burst sources, circumbinary disks around merging supermassive black holes in the cores of galaxies and quasars, and the profile and observable consequences of dark matter around supermassive black holes in galaxy cores, including the Milky Way. Most of these topics represent long-standing, fundamental problems in theoretical physics requiring large-scale computation for solution. Hence the approach involves to a significant degree large-scale computations on parallel machines, as well as analytical modeling. They comprise both initial value and evolution computations and treat vacuum spacetimes containing black holes as well as spacetimes containing realistic matter sources, magnetic fields and both electromagnetic and neutrino radiation ("multimessenger astronomy"). The results have important implications for astronomical observations, including those planned for gravitational wave interferometers, such as the Advanced LIGO/VIRGO network, GEO, KAGRA, the PTAs and eLISA.
