HLRB Project h0074
Simulation of neutron star merger
Max-Planck-Institut fuer Astrophysik
Proposing Institution
Max-Planck-Institut fuer Astrophysik
Project Manager
Andreas Bauswein
Karl-Schwarzschild-Str. 1
85741 Garching
Abstract
-- only for test account --The merging of neutron stars are fascinating events in many respects. From the astrophysical point of view they are linked to many different fields. They are certainly among the most promising sources for gravitational waves, and population synthesis studies predict that the upcoming gravitational wave detectors will measure signals from the inspiral and coalescence. Furthermore, as was shown in simulations, the gravitational waves of the final plunge and ring-down phases contain information about the poorly known nuclear equation of state. Beside that neutron star mergers were proposed to be the origin of short gamma-ray bursts, which are observed by several satellites. The observational data available so far support this idea, although further investigations theoretically and observationally are necessary. In addition, material that is ejected by a neutron star merger might contribute to the nucleosynthesis of r-process-elements, heavy elements created in an environment of high neutron fluxes. In order to confirm this, highly resolved simulations of neutron star mergers are needed.The realistic simulation of neutron star coalescence is very challenging, since many different physical aspects have to be appropriately treated. For instance the consideration of general relativistic effects is required as well as the inclusion of a microphysical equation of state. Because the knowledge of the properties of (hot) neutron star matter is incomplete, different descriptions of the equation of state have to be explored. For a comparative study of the influence of different equations of state and different initial configurations a high-performance code is essential. To allow for conclusions on nucleosynthesis the simulations should yield good resolution also and in particular of the surface-near layers of the neutron stars.The code which will be used for the proposed project meets all these requirements. A relativistic Smoothed Particle Hydrodynamic (SPH) scheme is implemented, while the gravity is described by the conformal flatness approximation of general relativity. The code is parallelized with OpenMP, for which the SPH approach turned out to be very advantageous. The requested test account will be mainly used to check the scalability and performance of the code on the HLRB IIsupercomputer of the Leibniz Rechenzentrum. The entire project finally aims at a systematic study of the aspects described above and moreover to provide data, which can be used in nucleosynthesis calculations. We intend to perform the first high-resolution relativistic simulations of neutron star coalescence with a detailed, microphysical treatment of the neutron star matter.
