2015/11/30 by William E. East, Vasileios Paschalidis, Frans Pretorius +1 · 138 citations
Physics and Astronomy · #Angular momentum #Astronomy #Astrophysics #Black hole (networking) #Classical mechanics #Gamma-ray bursts and supernovae #Gravitational wave #Kilonova #LIGO #Magnetic confinement fusion research #Neutron star #Physics #Pulsars and Gravitational Waves Research #X-ray binary #astro-ph.HE #gr-qc
paper · pdf · doi:10.1103/physrevd.93.024011
published in Physical review. D/Physical review. D. 93(2) (American Physical Society) · 24 pages, 18 figures; revised to match published version
openalex publication_date 2016/01/08 · arxiv created 2016/01/13 · arxiv updated 2016/01/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We perform general-relativistic hydrodynamical simulations of dynamical capture binary neutron star mergers, emphasizing the role played by the neutron star spin. Dynamical capture mergers may take place in globular clusters, as well as other dense stellar systems, where most neutron stars have large spins. We find significant variability in the merger outcome as a function of initial neutron star spin. For cases where the spin is aligned with the orbital angular momentum, the additional centrifugal support in the remnant hypermassive neutron star can prevent the prompt collapse to a black hole, while for antialigned cases the decreased total angular momentum can facilitate the collapse to a black hole. We show that even moderate spins can significantly increase the amount of ejected material, including the amount unbound with velocities greater than half the speed of light, leading to brighter electromagnetic signatures associated with kilonovae and interaction of the ejecta with the interstellar medium. Furthermore, we find that the initial neutron star spin can strongly affect the already rich phenomenology in the postmerger gravitational wave signatures that arise from the oscillation modes of the hypermassive neutron star. In several of our simulations, the resulting hypermassive neutron star develops the one-arm (m=1) spiral instability, the most pronounced cases being those with small but non-negligible neutron star spins. For long-lived hypermassive neutron stars, the presence of this instability leads to improved prospects for detecting these events through gravitational waves, and thus may give information about the neutron star equation of state.