Magnetized Hypermassive NeutronStar Collapse: A Central Engine for Short GammaRay Bursts
Abstract
A hypermassive neutron star (HMNS) is a possible transient formed after the merger of a neutronstar binary. In the latest axisymmetric magnetohydrodynamic simulations in full general relativity, we find that a magnetized HMNS undergoes “delayed” collapse to a rotating black hole (BH) as a result of angular momentum transport via magnetic braking and the magnetorotational instability. The outcome is a BH surrounded by a massive, hot torus with a collimated magnetic field. The torus accretes onto the BH at a quasisteady accretion rate ∼10M_{☉}/s; the lifetime of the torus is ∼10ms. The torus has a temperature ≳10^{12}K, leading to copious (νν̄) thermal radiation that could trigger a fireball. Therefore, the collapse of a HMNS is a promising scenario for generating shortduration gammaray bursts and an accompanying burst of gravitational waves and neutrinos.
 Publication:

Physical Review Letters
 Pub Date:
 January 2006
 DOI:
 10.1103/PhysRevLett.96.031102
 arXiv:
 arXiv:astroph/0511142
 Bibcode:
 2006PhRvL..96c1102S
 Keywords:

 04.25.Dm;
 04.40.Dg;
 97.60.Jd;
 98.70.Rz;
 Numerical relativity;
 Relativistic stars: structure stability and oscillations;
 Neutron stars;
 gammaray sources;
 gammaray bursts;
 Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 4 pages, 2 figures, submitted to Phys. Rev. Letter