Jet from binary neutron star merger with prompt black hole formation

TL;DR

This study presents a comprehensive simulation of a binary neutron star merger leading to prompt black hole formation, revealing jet formation, gravitational waves, neutrino emissions, and mass ejections over 1.5 seconds.

Contribution

First long-duration neutrino-radiation magnetohydrodynamics simulation capturing jet formation and associated phenomena in a prompt black hole formation merger.

Findings

Jet with luminosity ~10^{49} erg/s launched

Magnetosphere aligned with black hole spin axis

High luminosity phase lasts around 1 second

Abstract

We performed the longest numerical-relativity neutrino-radiation magnetohydrodynamics simulation for a binary neutron star merger that extends to $\approx1.5\mathrm{\,s}$ after the merger. We consider the binary model that undergoes the prompt collapse to a black hole after the merger with asymmetric mass 1.25$\,M_{\odot}$ and 1.65$\,M_{\odot}$ and SFHo equation of state. We find the Poynting flux-driven collimated outflow as well as the gravitational wave emission, neutrino emission, dynamical mass ejection, and post-merger mass ejection facilitated by magnetorotational instability-driven turbulent viscosity in a single self-consistent binary neutron star merger simulation. A magnetosphere dominated by the aligned global magnetic field penetrating the black hole develops along the black-hole spin axis after the turbulence in the remnant disk is enhanced. A jet with the Poynting flux with isotropic-equivalent luminosity of $\sim10^{49}\mathrm{\,erg/s}$ is launched, and the duration of the high luminosity is expected to be $O(1)\mathrm{\,s}$.