Coalescence of Binary Neutron Stars and Gravitational Radiation
Project/Area Number 
13640271

Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  NIIGATA UNIVERSITY 
Principal Investigator 
OOHARA Kenichi NIIGATA UNIVERSITY Faculty of Science, Associate Professor, 理学部, 助教授 (00183765)

Project Period (FY) 
2001 – 2002

Project Status 
Completed (Fiscal Year 2002)

Budget Amount *help 
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)

Keywords  General Relativity / Gravitational Waves / Neutron Star / Numerical Simulation 
Research Abstract 
We have performed numerical simulations for coalescing binary neutron stars using a 3dimensional general relativistic code and investigate radiation of gravitational waves. A stable code using maximal slicing and pseudominimal distortion condition has been obtained, where we found that it is important to calculate the secondderivative of the metric tensor with precision making use of the pseudominimal distortion condition. At first, some parts of the gravitational waves are reflected at the numerical boundary, but it is found to be fixed if the grid size is enlarged. We use a 475 × 475 grid in the Cartesian coordinate system. The CPU hours necessary to perform the simulation for each parameter set is approximately 100 hours on Fujitsu VPP5000 with 32 nodes. To evaluate the gravitational radiation, we implemented a gaugeinvariant wave extraction and compared the wave forms with a simple estimate of waves from metric perturbation. The energy spectrum of the waves was also evaluated to investigate the possibility that the excitation of the quasinormal modes of black hole, which may be formed after merger of two stars, can be caught. However, we need more precise calculation with finer grid and larger grid size from various initial data to obtain definite results. The following revision of the code remains for future research; more realistic initial data and other method of gaugeinvariant wave extraction. The required CPU hours will be reduced if slightly different coordinate conditions are used.

Report
(3 results)
Research Products
(8 results)