We present general relativistic numerical simulations of binary neutron star ( BNS ) mergers with different initial spin configurations .
We focus on models with stars of mass 1.4 M _ { \odot } each , which employ the equation of state ( EOS ) by Shen , Horowitz , and Teige , and which result in stable NSs as merger remnants .
For comparison , we consider two irrotational equal mass ( M = 1.35 \usk M _ { \odot } ) and unequal mass ( M = 1.29 , 1.42 \usk M _ { \odot } ) BNS models using the APR4 EOS , which result in a supramassive merger remnant .
We present visualizations of the fluid flow and temperature distribution and find a strong impact of the spin on vortex structure and nonaxisymmetric deformation .
We compute the radial mass distribution and the rotation profile in the equatorial plane using recently developed measures independent of spatial gauge , revealing slowly rotating cores that can be well approximated by the cores of spherical stars .
We also study the influence of the spin on the inspiral phase and the gravitational wave ( GW ) signal .
Using a newly developed analysis method , we further show that gravitational waveforms from BNS mergers can exhibit one or more phase jumps after merger , which occur together with minima of the strain amplitude .
We provide a natural explanation in terms of the remnant ’ s quadrupole moment , and show that cancellation effects due to phase jumps can have a strong impact on the GW power spectrum .
Finally , we discuss the impact of the spin on the amount of ejected matter .