Ruiz Milton, Shapiro Stuart L
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801.
Department of Astronomy and NCSA, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801.
Phys Rev D. 2017 Oct 15;96(8). doi: 10.1103/PhysRevD.96.084063. Epub 2017 Oct 30.
Inspiraling and merging binary neutron stars are not only important source of gravitational waves, but also promising candidates for coincident electromagnetic counterparts. These systems are thought to be progenitors of short gamma-ray bursts (sGRBs). We have shown previously that binary neutron star mergers that undergo collapse to a black hole surrounded by a magnetized accretion disk can drive magnetically powered jets. We now perform magnetohydrodynamic simulations in full general relativity of binary neutron stars mergers that undergo collapse to explore the possibility of jet formation from black hole- accretion disk remnants. We find that after - ~26(/1.8 ) ms ( is the ADM mass) following prompt black hole formation, there is no evidence of mass outflow or magnetic field collimation. The rapid formation of the black hole following merger prevents magnetic energy from approaching force-free values above the magnetic poles, which is required for the launching of a jet by the usual Blandford-Znajek mechanism. Detection of gravitational waves in coincidence with sGRBs may provide constraints on the nuclear equation of state (EOS): the fate of an NSNS merger-delayed or prompt collapse, and hence the appearance or nonappearance of an sGRB-depends on a critical value of the total mass of the binary, and this value is sensitive to the EOS.
旋进并合并的双中子星不仅是引力波的重要来源，也是产生电磁对应体的潜在候选者。这些系统被认为是短伽马射线暴（sGRBs）的前身。我们之前已经表明，双中子星合并后坍缩形成被磁化吸积盘环绕的黑洞时，可以驱动磁驱动喷流。我们现在在完全广义相对论下对双中子星合并并坍缩的过程进行磁流体动力学模拟，以探索从黑洞 - 吸积盘残骸形成喷流的可能性。我们发现，在迅速形成黑洞后的大约26（/1.8 ）毫秒（是ADM质量）内，没有质量外流或磁场准直的迹象。合并后黑洞的迅速形成阻止了磁能在磁极上方接近无力值，而这是通过通常的 Blandford - Znajek机制发射喷流所必需的。与sGRBs同时探测到引力波可能会对核态方程（EOS）施加限制：NSNS合并的命运——延迟坍缩还是迅速坍缩，进而sGRB的出现与否——取决于双星总质量的一个临界值，而这个值对EOS很敏感。
