Binary neutron star mergers and numerical relativity

Compact binary neutron star, a system composed of two neutron stars in close orbits, is one of the most promising sources for the gravitational-wave detectors such as advanced LIGO, VIRGO, and KAGRA. The merger of this system is also the most promising candidate for short-duration gamma-ray bursts for which we do not still know the progenitor, and a promising site for the production of heavy elements such as gold which have been produced by the rapid neutron capture process in the universe. Gravitational-wave detection and associated observation of the electromagnetic counterparts from binary neutron star mergers will test these hypotheses in the next decade and hopefully solve many unsolved issues. I will talk on these aspects on the neutron-star mergers emphasizing that the accurate prediction of the merger events by numerical studies is quite important.