The work to be carried out under this award will develop the needed infrastructure and apply it to study realistic compact binary systems that can give rise to gamma ray burst phenomena. To this end the required physics modules will be incorporated in a new infrastructure framework able to exploit the new generation of high performance computers. The implementations of this infrastructure will allow study of the system in depth, with the goal of predicting and interpreting aspects of observations of electromagnetic and gravitational waves.
This work serves to advance computational and numerical techniques for an exciting scientific problem, as well as the creation and dissemination of advanced tools for distributed computing. The research to be carried out has as its goal to give an unprecedented description of possible (short) gamma ray burst systems and to develop a new computational model to efficiently utilize petascale computing. Finally, this study involves the training of postdoctoral researchers, graduate students, and undergraduates.
We have investigated certain types of astrophysical, binary systems in which the members can be either neutron stars or black holes. Such systems are expected to follow decaying orbits and will eventually merge into a single black hole with some residual material surrounding it. The process of merger in this and similar systems is extremely energetic and will send off both electromagnetic waves and gravitational waves. The second of these waves have not yet been detected though a number of international experiments are attempting to measure them. Our work has focused on questions related to simulating these systems on computers. In particular, we have found that the accretion disk formed in such mergers will naturally be affected when the central black hole receives a kick due to the emission of gravitational radiation. Further, we have found that for a binary black hole merger in the presence of a magnetic field, the electromagnetic field can extract energy from the binary itself and produce jets that could be observable far from the binary. In addition, we have investigated the effects of more accurate descriptions of the matter interior to a neutron star on the merger process and we have calculated electromagnetic spectra from some of these systems.
