We perform a numerical-relativity simulation for the merger of binary neutron stars with 6 nuclear-theory-based equations of state ( EOSs ) described by piecewise polytropes .
Our purpose is to explore the dependence of the dynamical behavior of the binary neutron star merger and resulting gravitational waveforms on the EOS of the supernuclear-density matter .
The numerical results show that the merger process and the first outcome are classified into three types ; ( i ) a black hole is promptly formed , ( ii ) a short-lived hypermassive neutron star ( HMNS ) is formed , ( iii ) a long-lived HMNS is formed .
The type of the merger depends strongly on the EOS and on the total mass of the binaries .
For the EOS with which the maximum mass is larger than 2 M _ { \odot } , the lifetime of the HMNS is longer than 10 ms for a total mass m _ { 0 } = 2.7 M _ { \odot } .
A recent radio observation suggests that the maximum mass of spherical neutron stars is M _ { max } \geq 1.97 \pm 0.04 M _ { \odot } in one \sigma level .
This fact and our results support the possible existence of a HMNS soon after the onset of the merger for a typical binary neutron star with m _ { 0 } = 2.7 M _ { \odot } .
We also show that the torus mass surrounding the remnant black hole is correlated with the type of the merger process ; the torus mass could be large , \geq 0.1 M _ { \odot } , in the case that a long-lived HMNS is formed .
We also show that gravitational waves carry information of the merger process , the remnant , and the torus mass surrounding a black hole .